gamin binary package in Ubuntu Focal amd64

 Gamin is a file and directory monitoring system which allows
 applications to detect when a file or a directory has been added,
 removed or modified by somebody else.
 .
 It can be used by desktops like KDE, GNOME or Xfce to have their
 virtual file systems keep track of changes to files and directories.
 For example, if a file manager displays a directory to the user, and
 the user removes one of the files via the command-line, gamin will
 notify the file manager of this change so that it can update the
 directory display.
 .
 Gamin has been designed as a drop-in replacement for FAM with security
 and maintainability in mind and can use Linux's advanced inotify
 service when available.

Source package