gio:file-basename (file)

file -- a g:file object

The string containing the base name of the g:file object, or nil if the given g:file object is invalid.

Gets the base name, the last component of the path, for a given g:file object. If called for the toplevel of a system, such as the filesystem root or a URI like sftp://host/, it will return a single directory separator, and on Windows, possibly a drive letter.

The base name is a byte string, not UTF-8. It has no defined encoding or rules other than it may not contain zero bytes. If you want to use filenames in a user interface you should use the display name, see the g:file-get-parse-name function.