A [wiki](https://en.wikipedia.org/wiki/Wiki) is a collaborative space on the web. It is a common practice to use wikis to collect knowledge and share information.
To enable the wiki for a repository, visit the `Settings` page and activate `Enable Repository Wiki` in the `Advanced Section`. It will default to the built-in wiki which is described here, but you can add an URI to an external site the "Wiki" tab should link to.
> Be aware that the wiki, once enabled, is accessible for _everyone_ who has `read` access to your repository - on public repositories even unauthenticated guests can access the wiki.
To edit the wiki `write` permission to the repository is required, unless the `Allow anyone to edit the Wiki` setting is activated on the `Settings` page, in the `Advanced Settings` section.
Editing locally allows you to use your favorite editor (preferably with Markdown syntax check and highlighting) and manage additional assets like images.
To enhance the usability of your wiki you can add a custom sidebar and a footer that are shown on every page. The sidebar will be displayed to the right of the main content and the footer below.
To enable the sidebar, just add a file named `_Sidebar.md` to your wiki. For a footer the file must be named `_Footer.md`.
Both file types allow common Markdown syntax to adjust the presentation to your needs.
> These files starting with `_` are hidden, so in the web UI you need to manually browse for the files. E.g. for our user _knut_ and his _foobar_ repo: