Locked file messages, notifications and visual overlays are only informative and do not actually lock a file. They are automatically created when someone opens a files, saves changed content and keeps the file open. Alternatively a user can manually create a “lock” status. Automatically created locks are automatically removed once the file is closed. Manually created locks also have to be manually removed.
In any case, any Space member can remove a file lock.
If you want to find all locked files you can use the search function in TeamDrive. For more information on where to remove a file lock or on locking files in general, please view our enable write protection entry.