What exactly does "Synchronize Playlist with Dir(s)" from the <File> pull-down menu do? I'm looking for a definition like:

"The gtkpod database file (eg local_0.itdb) contains all meta-information about the the tracks in repository corresponding. The displayed information on the GUI reflects the current content of local_<some-number>.itdb. The 'Synchronize ...' command from the File pull-down menu calls a routine which compares the actual contents of the files on the hard disk (like id3tag information, md5sums, filenames etc.) with the local_<some number>.itdb file that corresponds to the repository which comprises the playlist in concern."

I've scoured the 'net and have not found an explicit definition for "Synchronize."