Replace @returns with @return, in /lib

lib/private/group.php

lib/private/group/dummy.php

lib/private/group/example.php

lib/private/helper.php

lib/private/installer.php

lib/private/l10n.php

lib/private/ocsclient.php

lib/private/request.php

lib/private/template/functions.php

lib/private/user.php

lib/private/user/backend.php

lib/private/user/database.php

lib/private/user/example.php

lib/private/user/http.php

lib/private/user/interface.php

lib/private/vobject.php

lib/public/itags.php

lib/public/util.php