Update metadata of user.

Executes network-level upgrade routines.

Filters the maximum upload file size allowed, in bytes.

Displays the site upload space quota setting form on the Edit Site Settings screen.

Determine whether to use CodePress.

Retrieves the URL to the admin area for the current user.

Deprecated functionality to validate an email address.

Retrieves the HTML list content for nav menu items.

Resets internal cache keys and structures.

Attempt to determine the real file type of a file.