diff --git a/bench_util/benches/op_baseline.rs b/bench_util/benches/op_baseline.rs
index 9c3ac16c4b..f8ae32b353 100644
--- a/bench_util/benches/op_baseline.rs
+++ b/bench_util/benches/op_baseline.rs
@@ -1,3 +1,5 @@
+// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
+
 use deno_bench_util::bench_or_profile;
 use deno_bench_util::bencher::{benchmark_group, Bencher};
 use deno_bench_util::{bench_js_async, bench_js_sync};
diff --git a/bench_util/benches/utf8.rs b/bench_util/benches/utf8.rs
index 363300d5e1..2bbf439b67 100644
--- a/bench_util/benches/utf8.rs
+++ b/bench_util/benches/utf8.rs
@@ -1,3 +1,5 @@
+// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
+
 use deno_bench_util::bench_js_sync_with;
 use deno_bench_util::bench_or_profile;
 use deno_bench_util::bencher::benchmark_group;
diff --git a/cli/bench/http/deno_http_flash_ops_spawn.js b/cli/bench/http/deno_http_flash_ops_spawn.js
index 6ee39a84a8..b9d11462ff 100644
--- a/cli/bench/http/deno_http_flash_ops_spawn.js
+++ b/cli/bench/http/deno_http_flash_ops_spawn.js
@@ -1,3 +1,5 @@
+// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
+
 if (Deno.build.os !== "linux") {
   throw new Error("SO_REUSEPORT is only supported on Linux");
 }
diff --git a/cli/bench/http/deno_http_flash_spawn.js b/cli/bench/http/deno_http_flash_spawn.js
index eb827b34b1..e47acffc59 100644
--- a/cli/bench/http/deno_http_flash_spawn.js
+++ b/cli/bench/http/deno_http_flash_spawn.js
@@ -1,3 +1,5 @@
+// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
+
 if (Deno.build.os !== "linux") {
   throw new Error("SO_REUSEPORT is only supported on Linux");
 }
diff --git a/cli/bench/http/deno_http_native_headers.js b/cli/bench/http/deno_http_native_headers.js
index 23ef1e0600..7c1eaa5832 100644
--- a/cli/bench/http/deno_http_native_headers.js
+++ b/cli/bench/http/deno_http_native_headers.js
@@ -1,3 +1,5 @@
+// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
+
 const addr = Deno.args[0] || "127.0.0.1:4500";
 const [hostname, port] = addr.split(":");
 const listener = Deno.listen({ hostname, port: Number(port) });
diff --git a/cli/bench/http/deno_http_ops.js b/cli/bench/http/deno_http_ops.js
index f65b32170f..3fd0bef316 100644
--- a/cli/bench/http/deno_http_ops.js
+++ b/cli/bench/http/deno_http_ops.js
@@ -1,3 +1,5 @@
+// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
+
 const addr = Deno.args[0] || "127.0.0.1:4500";
 const [hostname, port] = addr.split(":");
 const tcp = Deno.listen({ hostname, port: Number(port) });
diff --git a/cli/bench/http/node_reactdom_ssr.js b/cli/bench/http/node_reactdom_ssr.js
index 5e784b946a..f82b504d79 100644
--- a/cli/bench/http/node_reactdom_ssr.js
+++ b/cli/bench/http/node_reactdom_ssr.js
@@ -1,3 +1,5 @@
+// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
+
 var Gd = Object.create;
 var Ac = Object.defineProperty;
 var Xd = Object.getOwnPropertyDescriptor;
diff --git a/cli/bench/napi/bench.js b/cli/bench/napi/bench.js
index 5917d3a28c..63215a217c 100644
--- a/cli/bench/napi/bench.js
+++ b/cli/bench/napi/bench.js
@@ -1,3 +1,5 @@
+// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
+
 import { loadTestLibrary } from "../../../test_napi/common.js";
 
 const lib = loadTestLibrary();
diff --git a/cli/bench/stdio/stdio.js b/cli/bench/stdio/stdio.js
index 1d11c273dd..e53016df24 100644
--- a/cli/bench/stdio/stdio.js
+++ b/cli/bench/stdio/stdio.js
@@ -1,5 +1,6 @@
-// From https://github.com/just-js/benchmarks/tree/main/01-stdio
 // Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
+//
+// From https://github.com/just-js/benchmarks/tree/main/01-stdio
 
 const blocksize = parseInt(Deno.args[0] || 65536);
 const buf = new Uint8Array(blocksize);
diff --git a/cli/cache/parsed_source.rs b/cli/cache/parsed_source.rs
index 28547dcf6b..cef33e3549 100644
--- a/cli/cache/parsed_source.rs
+++ b/cli/cache/parsed_source.rs
@@ -1,3 +1,5 @@
+// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
+
 use std::collections::HashMap;
 use std::path::Path;
 use std::path::PathBuf;
diff --git a/cli/js.rs b/cli/js.rs
index 4bf3da6273..06a6a5fd9b 100644
--- a/cli/js.rs
+++ b/cli/js.rs
@@ -1,3 +1,5 @@
+// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
+
 use deno_core::Snapshot;
 use log::debug;
 use once_cell::sync::Lazy;
diff --git a/cli/lsp/client.rs b/cli/lsp/client.rs
index 25c97d9d52..b39678667f 100644
--- a/cli/lsp/client.rs
+++ b/cli/lsp/client.rs
@@ -1,3 +1,5 @@
+// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
+
 use std::future::Future;
 use std::pin::Pin;
 use std::sync::Arc;
diff --git a/cli/ops/bench.rs b/cli/ops/bench.rs
index 9b70cfa79c..2181a139c7 100644
--- a/cli/ops/bench.rs
+++ b/cli/ops/bench.rs
@@ -1,6 +1,9 @@
-use crate::tools::bench::BenchDescription;
-use crate::tools::bench::BenchEvent;
-use crate::tools::test::TestFilter;
+// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
+
+use std::sync::atomic::AtomicUsize;
+use std::sync::atomic::Ordering;
+use std::time;
+
 use deno_core::error::generic_error;
 use deno_core::error::AnyError;
 use deno_core::op;
@@ -12,12 +15,13 @@ use deno_runtime::permissions::ChildPermissionsArg;
 use deno_runtime::permissions::PermissionsContainer;
 use serde::Deserialize;
 use serde::Serialize;
-use std::sync::atomic::AtomicUsize;
-use std::sync::atomic::Ordering;
-use std::time;
 use tokio::sync::mpsc::UnboundedSender;
 use uuid::Uuid;
 
+use crate::tools::bench::BenchDescription;
+use crate::tools::bench::BenchEvent;
+use crate::tools::test::TestFilter;
+
 pub fn init(
   sender: UnboundedSender<BenchEvent>,
   filter: TestFilter,
diff --git a/cli/tests/unit/abort_controller_test.ts b/cli/tests/unit/abort_controller_test.ts
index 6b7bea899b..2df953773b 100644
--- a/cli/tests/unit/abort_controller_test.ts
+++ b/cli/tests/unit/abort_controller_test.ts
@@ -1,3 +1,5 @@
+// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
+
 import { assert, assertEquals } from "./test_util.ts";
 
 Deno.test(function basicAbortController() {
diff --git a/cli/tests/unit/command_test.ts b/cli/tests/unit/command_test.ts
index 2a0562c933..e7f9405354 100644
--- a/cli/tests/unit/command_test.ts
+++ b/cli/tests/unit/command_test.ts
@@ -1,4 +1,5 @@
-// Copyright 2018-2021 the Deno authors. All rights reserved. MIT license.
+// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
+
 import {
   assert,
   assertEquals,
diff --git a/cli/tests/unit/dom_exception_test.ts b/cli/tests/unit/dom_exception_test.ts
index b6b6a44404..d0a0b8a942 100644
--- a/cli/tests/unit/dom_exception_test.ts
+++ b/cli/tests/unit/dom_exception_test.ts
@@ -1,3 +1,5 @@
+// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
+
 import {
   assertEquals,
   assertNotEquals,
diff --git a/cli/tests/unit/fs_events_test.ts b/cli/tests/unit/fs_events_test.ts
index 2888a05f88..cdfb676570 100644
--- a/cli/tests/unit/fs_events_test.ts
+++ b/cli/tests/unit/fs_events_test.ts
@@ -1,4 +1,5 @@
-// Copyright 2018-2019 the Deno authors. All rights reserved. MIT license.
+// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
+
 import { assert, assertEquals, assertThrows, delay } from "./test_util.ts";
 
 // TODO(ry) Add more tests to specify format.
diff --git a/cli/tests/unit/network_interfaces_test.ts b/cli/tests/unit/network_interfaces_test.ts
index a0e6e691a1..287b7d421f 100644
--- a/cli/tests/unit/network_interfaces_test.ts
+++ b/cli/tests/unit/network_interfaces_test.ts
@@ -1,3 +1,5 @@
+// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
+
 import { assert } from "./test_util.ts";
 
 Deno.test(
diff --git a/cli/tests/unit/opcall_test.ts b/cli/tests/unit/opcall_test.ts
index 9707318555..61c3c88491 100644
--- a/cli/tests/unit/opcall_test.ts
+++ b/cli/tests/unit/opcall_test.ts
@@ -1,3 +1,5 @@
+// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
+
 import { assert, assertStringIncludes, unreachable } from "./test_util.ts";
 
 Deno.test(async function sendAsyncStackTrace() {
diff --git a/cli/tests/unit/path_from_url_test.ts b/cli/tests/unit/path_from_url_test.ts
index f375d84f4f..9842c29c2b 100644
--- a/cli/tests/unit/path_from_url_test.ts
+++ b/cli/tests/unit/path_from_url_test.ts
@@ -1,3 +1,5 @@
+// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
+
 import { assertEquals, assertThrows } from "./test_util.ts";
 
 // @ts-expect-error TypeScript (as of 3.7) does not support indexing namespaces by symbol
diff --git a/cli/tests/unit/read_text_file_test.ts b/cli/tests/unit/read_text_file_test.ts
index 5e455c5832..e78276dde8 100644
--- a/cli/tests/unit/read_text_file_test.ts
+++ b/cli/tests/unit/read_text_file_test.ts
@@ -1,3 +1,5 @@
+// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
+
 import {
   assert,
   assertEquals,
diff --git a/cli/tests/unit/ref_unref_test.ts b/cli/tests/unit/ref_unref_test.ts
index da6e95efc8..7ce72a1708 100644
--- a/cli/tests/unit/ref_unref_test.ts
+++ b/cli/tests/unit/ref_unref_test.ts
@@ -1,3 +1,5 @@
+// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
+
 import { assertNotEquals, execCode } from "./test_util.ts";
 
 Deno.test("[unrefOp] unref'ing invalid ops does not have effects", async () => {
diff --git a/cli/tests/unit/structured_clone_test.ts b/cli/tests/unit/structured_clone_test.ts
index c60b38a8a7..722c9c8cc5 100644
--- a/cli/tests/unit/structured_clone_test.ts
+++ b/cli/tests/unit/structured_clone_test.ts
@@ -1,3 +1,5 @@
+// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
+
 import { assert, assertEquals, assertThrows } from "./test_util.ts";
 
 // Basic tests for the structured clone algorithm. Mainly tests TypeScript
diff --git a/cli/tests/unit/version_test.ts b/cli/tests/unit/version_test.ts
index 3b371a2bcf..55a4bc6c97 100644
--- a/cli/tests/unit/version_test.ts
+++ b/cli/tests/unit/version_test.ts
@@ -1,3 +1,5 @@
+// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
+
 import { assert, assertEquals } from "./test_util.ts";
 
 Deno.test(function version() {
diff --git a/cli/tests/unit/wasm_test.ts b/cli/tests/unit/wasm_test.ts
index 03ed0e2981..73d243de8f 100644
--- a/cli/tests/unit/wasm_test.ts
+++ b/cli/tests/unit/wasm_test.ts
@@ -1,3 +1,5 @@
+// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
+
 import { assert, assertEquals, assertRejects } from "./test_util.ts";
 
 // The following blob can be created by taking the following s-expr and pass
diff --git a/cli/tests/unit/webcrypto_test.ts b/cli/tests/unit/webcrypto_test.ts
index 86d9f38ab7..c522bf1e6e 100644
--- a/cli/tests/unit/webcrypto_test.ts
+++ b/cli/tests/unit/webcrypto_test.ts
@@ -1,3 +1,5 @@
+// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
+
 import {
   assert,
   assertEquals,
diff --git a/cli/tests/unit/webgpu_test.ts b/cli/tests/unit/webgpu_test.ts
index c903736f8d..decceb0f91 100644
--- a/cli/tests/unit/webgpu_test.ts
+++ b/cli/tests/unit/webgpu_test.ts
@@ -1,3 +1,5 @@
+// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
+
 import { assert, assertEquals } from "./test_util.ts";
 
 let isCI: boolean;
diff --git a/cli/tests/unit/write_text_file_test.ts b/cli/tests/unit/write_text_file_test.ts
index c835349284..8ce0ea6020 100644
--- a/cli/tests/unit/write_text_file_test.ts
+++ b/cli/tests/unit/write_text_file_test.ts
@@ -1,3 +1,5 @@
+// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
+
 import {
   assert,
   assertEquals,
diff --git a/cli/tools/coverage/merge.rs b/cli/tools/coverage/merge.rs
index 7fe382d240..29d26da3c6 100644
--- a/cli/tools/coverage/merge.rs
+++ b/cli/tools/coverage/merge.rs
@@ -1,6 +1,7 @@
+// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
+//
 // Forked from https://github.com/demurgos/v8-coverage/tree/d0ca18da8740198681e0bc68971b0a6cdb11db3e/rust
 // Copyright 2021 Charles Samborski. All rights reserved. MIT license.
-// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
 
 use super::json_types::CoverageRange;
 use super::json_types::FunctionCoverage;
diff --git a/cli/tools/coverage/range_tree.rs b/cli/tools/coverage/range_tree.rs
index 19b3257f87..8b3d36cd81 100644
--- a/cli/tools/coverage/range_tree.rs
+++ b/cli/tools/coverage/range_tree.rs
@@ -1,6 +1,7 @@
+// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
+//
 // Forked from https://github.com/demurgos/v8-coverage/tree/d0ca18da8740198681e0bc68971b0a6cdb11db3e/rust
 // Copyright 2021 Charles Samborski. All rights reserved. MIT license.
-// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
 
 use super::json_types::CoverageRange;
 use std::iter::Peekable;
diff --git a/cli/util/console.rs b/cli/util/console.rs
index c36b274db6..ac78ca4df5 100644
--- a/cli/util/console.rs
+++ b/cli/util/console.rs
@@ -1,3 +1,5 @@
+// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
+
 use deno_runtime::ops::tty::ConsoleSize;
 
 /// Gets the console size.
diff --git a/cli/util/path.rs b/cli/util/path.rs
index 6df982f4ed..76e2a1b6fa 100644
--- a/cli/util/path.rs
+++ b/cli/util/path.rs
@@ -1,3 +1,5 @@
+// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
+
 use std::borrow::Cow;
 use std::path::Path;
 use std::path::PathBuf;
diff --git a/cli/worker.rs b/cli/worker.rs
index 2f8a9b6873..7e06166505 100644
--- a/cli/worker.rs
+++ b/cli/worker.rs
@@ -1,3 +1,5 @@
+// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
+
 use std::path::PathBuf;
 use std::rc::Rc;
 use std::sync::Arc;
diff --git a/core/error_codes.rs b/core/error_codes.rs
index 6a8dd9fa3a..874aa4ec64 100644
--- a/core/error_codes.rs
+++ b/core/error_codes.rs
@@ -1,3 +1,5 @@
+// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
+
 use anyhow::Error;
 
 pub fn get_error_code(err: &Error) -> Option<&'static str> {
diff --git a/core/snapshot_util.rs b/core/snapshot_util.rs
index bacc0c6aeb..b35cabbfa9 100644
--- a/core/snapshot_util.rs
+++ b/core/snapshot_util.rs
@@ -1,9 +1,12 @@
+// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
+
+use std::path::Path;
+use std::path::PathBuf;
+
 use crate::Extension;
 use crate::JsRuntime;
 use crate::RuntimeOptions;
 use crate::Snapshot;
-use std::path::Path;
-use std::path::PathBuf;
 
 pub type CompressionCb = dyn Fn(&mut Vec<u8>, &[u8]);
 
diff --git a/ext/broadcast_channel/in_memory_broadcast_channel.rs b/ext/broadcast_channel/in_memory_broadcast_channel.rs
index 595a7cc13a..7c9c68ae0d 100644
--- a/ext/broadcast_channel/in_memory_broadcast_channel.rs
+++ b/ext/broadcast_channel/in_memory_broadcast_channel.rs
@@ -1,14 +1,16 @@
 // Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
 
-use crate::BroadcastChannel;
+use std::sync::Arc;
+
 use async_trait::async_trait;
 use deno_core::error::AnyError;
 use deno_core::parking_lot::Mutex;
-use std::sync::Arc;
 use tokio::sync::broadcast;
 use tokio::sync::mpsc;
 use uuid::Uuid;
 
+use crate::BroadcastChannel;
+
 #[derive(Clone)]
 pub struct InMemoryBroadcastChannel(Arc<Mutex<broadcast::Sender<Message>>>);
 
diff --git a/ext/crypto/decrypt.rs b/ext/crypto/decrypt.rs
index c83ff55bd9..6c4d5b6ba5 100644
--- a/ext/crypto/decrypt.rs
+++ b/ext/crypto/decrypt.rs
@@ -1,4 +1,5 @@
-use crate::shared::*;
+// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
+
 use aes::cipher::block_padding::Pkcs7;
 use aes::cipher::BlockDecryptMut;
 use aes::cipher::KeyIvInit;
@@ -29,6 +30,8 @@ use sha2::Sha256;
 use sha2::Sha384;
 use sha2::Sha512;
 
+use crate::shared::*;
+
 #[derive(Deserialize)]
 #[serde(rename_all = "camelCase")]
 pub struct DecryptOptions {
diff --git a/ext/crypto/ed25519.rs b/ext/crypto/ed25519.rs
index b7ff99d8b1..898366bbc1 100644
--- a/ext/crypto/ed25519.rs
+++ b/ext/crypto/ed25519.rs
@@ -1,3 +1,5 @@
+// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
+
 use deno_core::error::AnyError;
 use deno_core::op;
 use deno_core::ZeroCopyBuf;
diff --git a/ext/crypto/encrypt.rs b/ext/crypto/encrypt.rs
index 9420acdbd5..f34e0cbc6b 100644
--- a/ext/crypto/encrypt.rs
+++ b/ext/crypto/encrypt.rs
@@ -1,4 +1,4 @@
-use crate::shared::*;
+// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
 
 use aes::cipher::block_padding::Pkcs7;
 use aes::cipher::BlockEncryptMut;
@@ -31,6 +31,8 @@ use sha2::Sha256;
 use sha2::Sha384;
 use sha2::Sha512;
 
+use crate::shared::*;
+
 #[derive(Deserialize)]
 #[serde(rename_all = "camelCase")]
 pub struct EncryptOptions {
diff --git a/ext/crypto/export_key.rs b/ext/crypto/export_key.rs
index 0cbb2f6764..ec76bac928 100644
--- a/ext/crypto/export_key.rs
+++ b/ext/crypto/export_key.rs
@@ -1,4 +1,5 @@
-use crate::shared::*;
+// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
+
 use const_oid::AssociatedOid;
 use const_oid::ObjectIdentifier;
 use deno_core::error::custom_error;
@@ -15,6 +16,8 @@ use spki::der::Decode;
 use spki::der::Encode;
 use spki::AlgorithmIdentifier;
 
+use crate::shared::*;
+
 #[derive(Deserialize)]
 #[serde(rename_all = "camelCase")]
 pub struct ExportKeyOptions {
diff --git a/ext/crypto/generate_key.rs b/ext/crypto/generate_key.rs
index 9ecbb8d117..2a9452c433 100644
--- a/ext/crypto/generate_key.rs
+++ b/ext/crypto/generate_key.rs
@@ -1,4 +1,5 @@
-use crate::shared::*;
+// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
+
 use deno_core::error::AnyError;
 use deno_core::op;
 use deno_core::ZeroCopyBuf;
@@ -12,6 +13,8 @@ use rsa::BigUint;
 use rsa::RsaPrivateKey;
 use serde::Deserialize;
 
+use crate::shared::*;
+
 // Allowlist for RSA public exponents.
 static PUB_EXPONENT_1: Lazy<BigUint> =
   Lazy::new(|| BigUint::from_u64(3).unwrap());
diff --git a/ext/crypto/import_key.rs b/ext/crypto/import_key.rs
index 07c7f3f6fc..42eab0e6ca 100644
--- a/ext/crypto/import_key.rs
+++ b/ext/crypto/import_key.rs
@@ -1,5 +1,5 @@
-use crate::key::CryptoNamedCurve;
-use crate::shared::*;
+// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
+
 use deno_core::error::AnyError;
 use deno_core::op;
 use deno_core::ZeroCopyBuf;
@@ -12,6 +12,9 @@ use serde::Serialize;
 use spki::der::Decode;
 use spki::der::Encode;
 
+use crate::key::CryptoNamedCurve;
+use crate::shared::*;
+
 #[derive(Deserialize)]
 #[serde(rename_all = "camelCase")]
 pub enum KeyData {
diff --git a/ext/crypto/shared.rs b/ext/crypto/shared.rs
index d2f7d53e82..4ecb35dc27 100644
--- a/ext/crypto/shared.rs
+++ b/ext/crypto/shared.rs
@@ -1,3 +1,5 @@
+// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
+
 use std::borrow::Cow;
 
 use deno_core::error::custom_error;
diff --git a/ext/crypto/x25519.rs b/ext/crypto/x25519.rs
index 1e64e99092..0ecdf4ddc0 100644
--- a/ext/crypto/x25519.rs
+++ b/ext/crypto/x25519.rs
@@ -1,3 +1,5 @@
+// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
+
 use curve25519_dalek::montgomery::MontgomeryPoint;
 use deno_core::error::AnyError;
 use deno_core::op;
diff --git a/ext/flash/chunked.rs b/ext/flash/chunked.rs
index d414f211ea..711dd717d4 100644
--- a/ext/flash/chunked.rs
+++ b/ext/flash/chunked.rs
@@ -1,7 +1,8 @@
+// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
+//
 // Based on https://github.com/frewsxcv/rust-chunked-transfer/blob/5c08614458580f9e7a85124021006d83ce1ed6e9/src/decoder.rs
 // Copyright 2015 The tiny-http Contributors
 // Copyright 2015 The rust-chunked-transfer Contributors
-// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
 
 use std::error::Error;
 use std::fmt;
diff --git a/ext/flash/sendfile.rs b/ext/flash/sendfile.rs
index 43b5323a40..92e8f2bb78 100644
--- a/ext/flash/sendfile.rs
+++ b/ext/flash/sendfile.rs
@@ -1,5 +1,5 @@
-// Forked from https://github.com/Thomasdezeeuw/sendfile/blob/024f82cd4dede9048392a5bd6d8afcd4d5aa83d5/src/lib.rs
 // Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
+// Forked from https://github.com/Thomasdezeeuw/sendfile/blob/024f82cd4dede9048392a5bd6d8afcd4d5aa83d5/src/lib.rs
 
 use std::future::Future;
 use std::io;
diff --git a/ext/flash/socket.rs b/ext/flash/socket.rs
index 8256be8a0c..77881d5363 100644
--- a/ext/flash/socket.rs
+++ b/ext/flash/socket.rs
@@ -1,12 +1,13 @@
+// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
+
+use std::cell::UnsafeCell;
+use std::future::Future;
+use std::io::{Read, Write};
+use std::pin::Pin;
+use std::sync::{Arc, Mutex};
+
 use deno_core::error::AnyError;
 use mio::net::TcpStream;
-use std::{
-  cell::UnsafeCell,
-  future::Future,
-  io::{Read, Write},
-  pin::Pin,
-  sync::{Arc, Mutex},
-};
 use tokio::sync::mpsc;
 
 use crate::ParseStatus;
diff --git a/ext/node/module_es_shim.js b/ext/node/module_es_shim.js
index 164e18db53..f32006b4a5 100644
--- a/ext/node/module_es_shim.js
+++ b/ext/node/module_es_shim.js
@@ -1,3 +1,5 @@
+// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
+
 const m = Deno[Deno.internal].require.Module;
 export const _cache = m._cache;
 export const _extensions = m._extensions;
diff --git a/ext/node/path.rs b/ext/node/path.rs
index 8477fe7137..f0ce52002d 100644
--- a/ext/node/path.rs
+++ b/ext/node/path.rs
@@ -1,3 +1,5 @@
+// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
+
 use std::path::Component;
 use std::path::PathBuf;
 
diff --git a/ext/url/benches/url_ops.rs b/ext/url/benches/url_ops.rs
index 63810733dd..2bf113f540 100644
--- a/ext/url/benches/url_ops.rs
+++ b/ext/url/benches/url_ops.rs
@@ -1,3 +1,5 @@
+// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
+
 use deno_bench_util::bench_js_sync;
 use deno_bench_util::bench_or_profile;
 use deno_bench_util::bencher::{benchmark_group, Bencher};
diff --git a/ext/url/urlpattern.rs b/ext/url/urlpattern.rs
index 99fd216644..dcb3eaac8f 100644
--- a/ext/url/urlpattern.rs
+++ b/ext/url/urlpattern.rs
@@ -1,3 +1,5 @@
+// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
+
 use deno_core::error::type_error;
 use deno_core::error::AnyError;
 use deno_core::op;
diff --git a/ext/web/benches/encoding.rs b/ext/web/benches/encoding.rs
index 8c9eaeb6c0..01fba9e662 100644
--- a/ext/web/benches/encoding.rs
+++ b/ext/web/benches/encoding.rs
@@ -1,8 +1,9 @@
-use deno_core::Extension;
+// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
 
 use deno_bench_util::bench_js_sync;
 use deno_bench_util::bench_or_profile;
 use deno_bench_util::bencher::{benchmark_group, Bencher};
+use deno_core::Extension;
 use deno_web::BlobStore;
 
 struct Permissions;
diff --git a/ext/web/benches/timers_ops.rs b/ext/web/benches/timers_ops.rs
index 2ba93c5e13..024d523604 100644
--- a/ext/web/benches/timers_ops.rs
+++ b/ext/web/benches/timers_ops.rs
@@ -1,8 +1,9 @@
-use deno_core::Extension;
+// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
 
 use deno_bench_util::bench_js_async;
 use deno_bench_util::bench_or_profile;
 use deno_bench_util::bencher::{benchmark_group, Bencher};
+use deno_core::Extension;
 use deno_web::BlobStore;
 
 struct Permissions;
diff --git a/ext/web/blob.rs b/ext/web/blob.rs
index 24cd13454e..e4ba93a2f7 100644
--- a/ext/web/blob.rs
+++ b/ext/web/blob.rs
@@ -1,18 +1,19 @@
-use async_trait::async_trait;
-use deno_core::error::type_error;
-use deno_core::op;
+// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
 
-use deno_core::parking_lot::Mutex;
-use deno_core::url::Url;
-use deno_core::ZeroCopyBuf;
-use serde::{Deserialize, Serialize};
 use std::cell::RefCell;
 use std::collections::HashMap;
 use std::fmt::Debug;
 use std::rc::Rc;
 use std::sync::Arc;
 
+use async_trait::async_trait;
+use deno_core::error::type_error;
 use deno_core::error::AnyError;
+use deno_core::op;
+use deno_core::parking_lot::Mutex;
+use deno_core::url::Url;
+use deno_core::ZeroCopyBuf;
+use serde::{Deserialize, Serialize};
 use uuid::Uuid;
 
 use crate::Location;
diff --git a/ext/web/message_port.rs b/ext/web/message_port.rs
index 48c899216a..f287fc82d7 100644
--- a/ext/web/message_port.rs
+++ b/ext/web/message_port.rs
@@ -1,3 +1,5 @@
+// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
+
 use std::borrow::Cow;
 use std::cell::RefCell;
 use std::rc::Rc;
diff --git a/ops/fast_call.rs b/ops/fast_call.rs
index f2ed8cb2d7..b8fdf91bfe 100644
--- a/ops/fast_call.rs
+++ b/ops/fast_call.rs
@@ -1,6 +1,6 @@
-/// Code generation for V8 fast calls.
-use crate::optimizer::FastValue;
-use crate::optimizer::Optimizer;
+// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
+//! Code generation for V8 fast calls.
+
 use pmutil::{q, Quote, ToTokensExt};
 use proc_macro2::{Span, TokenStream};
 use quote::quote;
@@ -9,6 +9,9 @@ use syn::{
   Ident, ItemFn, ItemImpl, Path, PathArguments, PathSegment, Type, TypePath,
 };
 
+use crate::optimizer::FastValue;
+use crate::optimizer::Optimizer;
+
 pub(crate) struct FastImplItems {
   pub(crate) impl_and_fn: TokenStream,
   pub(crate) decl: TokenStream,
diff --git a/ops/optimizer.rs b/ops/optimizer.rs
index 2d68a296fd..3f22a867b8 100644
--- a/ops/optimizer.rs
+++ b/ops/optimizer.rs
@@ -1,10 +1,13 @@
-/// Optimizer for #[op]
-use crate::Op;
-use pmutil::{q, Quote};
-use proc_macro2::TokenStream;
+// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
+//! Optimizer for #[op]
+
 use std::collections::BTreeMap;
 use std::fmt::Debug;
 use std::fmt::Formatter;
+
+use pmutil::{q, Quote};
+use proc_macro2::TokenStream;
+
 use syn::{
   parse_quote, punctuated::Punctuated, token::Colon2,
   AngleBracketedGenericArguments, FnArg, GenericArgument, PatType, Path,
@@ -12,6 +15,8 @@ use syn::{
   TypeReference, TypeSlice, TypeTuple,
 };
 
+use crate::Op;
+
 #[derive(Debug)]
 pub(crate) enum BailoutReason {
   // Recoverable errors
diff --git a/runtime/js/40_spawn.js b/runtime/js/40_spawn.js
index 9d4aa3e9f2..de733d7eb1 100644
--- a/runtime/js/40_spawn.js
+++ b/runtime/js/40_spawn.js
@@ -1,4 +1,4 @@
-// Copyright 2018-2021 the Deno authors. All rights reserved. MIT license.
+// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
 "use strict";
 
 ((window) => {
diff --git a/runtime/ops/http.rs b/runtime/ops/http.rs
index a531deb842..51562589ea 100644
--- a/runtime/ops/http.rs
+++ b/runtime/ops/http.rs
@@ -1,3 +1,5 @@
+// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
+
 use std::cell::RefCell;
 use std::rc::Rc;
 
diff --git a/runtime/ops/spawn.rs b/runtime/ops/spawn.rs
index f552e96907..e5bf10cf05 100644
--- a/runtime/ops/spawn.rs
+++ b/runtime/ops/spawn.rs
@@ -1,4 +1,4 @@
-// Copyright 2018-2021 the Deno authors. All rights reserved. MIT license.
+// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
 
 use super::io::ChildStderrResource;
 use super::io::ChildStdinResource;
diff --git a/serde_v8/magic/u16string.rs b/serde_v8/magic/u16string.rs
index 22868ccfb2..11554738af 100644
--- a/serde_v8/magic/u16string.rs
+++ b/serde_v8/magic/u16string.rs
@@ -1,6 +1,9 @@
-use super::transl8::{impl_magic, impl_wrapper, FromV8, ToV8};
+// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
+
 use crate::Error;
 
+use super::transl8::{impl_magic, impl_wrapper, FromV8, ToV8};
+
 impl_wrapper!(
   pub struct U16String(Vec<u16>);
 );
diff --git a/test_ffi/tests/event_loop_integration.ts b/test_ffi/tests/event_loop_integration.ts
index c3b34cc8ff..e44c66ab69 100644
--- a/test_ffi/tests/event_loop_integration.ts
+++ b/test_ffi/tests/event_loop_integration.ts
@@ -1,3 +1,5 @@
+// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
+
 const targetDir = Deno.execPath().replace(/[^\/\\]+$/, "");
 const [libPrefix, libSuffix] = {
   darwin: ["lib", "dylib"],
diff --git a/test_napi/src/primitives.rs b/test_napi/src/primitives.rs
index 2d951ebfa3..e29c7c368b 100644
--- a/test_napi/src/primitives.rs
+++ b/test_napi/src/primitives.rs
@@ -1,3 +1,5 @@
+// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
+
 use crate::assert_napi_ok;
 use crate::napi_new_property;
 use napi_sys::*;
diff --git a/test_util/src/assertions.rs b/test_util/src/assertions.rs
index ecee14b1f9..a004530b6e 100644
--- a/test_util/src/assertions.rs
+++ b/test_util/src/assertions.rs
@@ -1,3 +1,5 @@
+// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
+
 #[macro_export]
 macro_rules! assert_ends_with {
   ($left:expr, $right:expr $(,)?) => {
diff --git a/test_util/src/npm.rs b/test_util/src/npm.rs
index 6e393d8353..738a1090aa 100644
--- a/test_util/src/npm.rs
+++ b/test_util/src/npm.rs
@@ -1,3 +1,5 @@
+// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
+
 use std::collections::HashMap;
 use std::fs;
 
diff --git a/test_util/src/pty.rs b/test_util/src/pty.rs
index 4970e08f43..b2d7201ae4 100644
--- a/test_util/src/pty.rs
+++ b/test_util/src/pty.rs
@@ -1,3 +1,5 @@
+// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
+
 use std::collections::HashMap;
 use std::io::Read;
 use std::path::Path;
diff --git a/test_util/src/temp_dir.rs b/test_util/src/temp_dir.rs
index cab55cc14d..01dce8f1ab 100644
--- a/test_util/src/temp_dir.rs
+++ b/test_util/src/temp_dir.rs
@@ -1,3 +1,5 @@
+// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
+
 use std::fs;
 use std::path::Path;
 use std::path::PathBuf;
diff --git a/tools/README.md b/tools/README.md
index 59860ca1b1..e88f8d8928 100644
--- a/tools/README.md
+++ b/tools/README.md
@@ -72,3 +72,16 @@ on top, somewhat similar to `git subtree`.
 2. Run `./tools/wgpu_sync.js`
 3. Double check changes, possibly patch
 4. Commit & send a PR with the updates
+
+## copyright_checker.js
+
+`copyright_checker.js` is used to check copyright headers in the codebase.
+
+To run the _copyright checker_:
+
+```sh
+deno run --allow-read --allow-run --unstable  ./tools/copyright_checker.js
+```
+
+Then it will check all code files in the repository and report any files that
+are not properly licensed.
diff --git a/tools/copyright_checker.js b/tools/copyright_checker.js
new file mode 100644
index 0000000000..706f59dbdf
--- /dev/null
+++ b/tools/copyright_checker.js
@@ -0,0 +1,84 @@
+#!/usr/bin/env -S deno run --unstable --allow-read --allow-run
+// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
+
+import { getSources, ROOT_PATH } from "./util.js";
+
+const buffer = new Uint8Array(1024);
+const textDecoder = new TextDecoder();
+
+async function readFirstPartOfFile(filePath) {
+  const file = await Deno.open(filePath, { read: true });
+  try {
+    const byteCount = await file.read(buffer);
+    return textDecoder.decode(buffer.slice(0, byteCount ?? 0));
+  } finally {
+    file.close();
+  }
+}
+
+async function checkCopyright() {
+  const sourceFiles = await getSources(ROOT_PATH, [
+    // js and ts
+    "*.js",
+    "*.ts",
+    ":!:.github/mtime_cache/action.js",
+    ":!:cli/tests/testdata/**",
+    ":!:cli/bench/testdata/**",
+    ":!:cli/tsc/dts/**",
+    ":!:cli/tsc/*typescript.js",
+    ":!:cli/tsc/compiler.d.ts",
+    ":!:test_util/wpt/**",
+    ":!:tools/**", // these files are starts with `#!/usr/bin/env`
+    ":!:cli/tools/init/templates/**",
+
+    // rust
+    "*.rs",
+    ":!:ops/optimizer_tests/**",
+
+    // toml
+    "*Cargo.toml",
+  ]);
+
+  let totalCount = 0;
+  const sourceFilesSet = new Set(sourceFiles);
+
+  for (const file of sourceFilesSet) {
+    const ERROR_MSG = "Copyright header is missing: ";
+
+    const fileText = await readFirstPartOfFile(file);
+    if (file.endsWith("Cargo.toml")) {
+      if (
+        !fileText.startsWith(
+          "# Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.",
+        )
+      ) {
+        console.log(ERROR_MSG + file);
+        totalCount += 1;
+      }
+      continue;
+    }
+
+    if (
+      !fileText.startsWith(
+        "// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.",
+      )
+    ) {
+      console.log(ERROR_MSG + file);
+      totalCount += 1;
+    }
+  }
+
+  console.log("\nTotal errors: " + totalCount);
+
+  if (totalCount > 0) {
+    Deno.exit(1);
+  }
+}
+
+async function main() {
+  await Deno.chdir(ROOT_PATH);
+
+  await checkCopyright();
+}
+
+await main();