diff --git a/docs/admin/config-cheat-sheet.md b/docs/admin/config-cheat-sheet.md
index face3b31..ae087ac3 100644
--- a/docs/admin/config-cheat-sheet.md
+++ b/docs/admin/config-cheat-sheet.md
@@ -672,6 +672,7 @@ And the following unique queues:
 - `DEFAULT_ALLOW_ONLY_CONTRIBUTORS_TO_TRACK_TIME`: **true**: Only allow users with write permissions to track time.
 - `EMAIL_DOMAIN_ALLOWLIST`: **\<empty\>**: If non-empty, comma separated list of domain names that can only be used to register on this instance, wildcard is supported.
 - `EMAIL_DOMAIN_BLOCKLIST`: **\<empty\>**: If non-empty, comma separated list of domain names that cannot be used to register on this instance, wildcard is supported.
+- `EMAIL_DOMAIN_BLOCK_DISPOSABLE`: **false**: Enable this to append a list of known temporary/disposable email domains as compiled by [disposable-email-domains](https://github.com/disposable-email-domains/disposable-email-domains) to the block list.
 - `SHOW_REGISTRATION_BUTTON`: **! DISABLE_REGISTRATION**: Show Registration Button
 - `SHOW_MILESTONES_DASHBOARD_PAGE`: **true** Enable this to show the milestones dashboard page - a view of all the user's milestones
 - `AUTO_WATCH_NEW_REPOS`: **true**: Enable this to let all organisation users watch new repos when they are created