wp-includes/ms-deprecated.php:129Deprecated functionality to retrieve user information.
$usernamestringfunction get_user_details( $username ) { _deprecated_function( __FUNCTION__, '3.0.0', 'get_user_by()' ); return get_user_by('login', $username);}Introduced in MU (3.0.0). Unchanged from 6.7.7 through 7.1.0.
Signature, return type and hooks compared across 5 parsed releases.
src/wp-includes/ms-deprecated.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.