When I Import a Playlist, Does Rekordbox Also Import The Tracks in that Playlist Again?

What exactly does importing a playlist do?  Does it import the xml file entry that tells Rekordbox that these songs are in this playlist?  Or does it take the entire contents, track information and all, and reimport that as well?

I recently started using Rekordbuddy to sync between Serato DJ and Rekordbox.  As my playlists and tracks are updated in Serato, I want those changes updated in Rekordbox.  Rekordbuddy does a fine job of updating the rekordbox.xml file, but when I import new/updated playlists, does rekordbox "reimport" the track info for every track in there as well?  does rekordbox work on a "smart system" to compare the current playlists and see if there are changes to the playlist being imported?  Does it know that a lot of songs in "updated" playlists are already in the collection and many have been unchanged?

I ask because it takes a long time to update my "playlist collection" in rekordbox through importing.  I feel like it should only update the playlists xml files and only import new tracks/reimport changed tracks, as the majority of playlist tracks are already in my collection (fully analyzed).

Also, does importing playlists take care of analyzing the tracks in the playlist that may be new or updated?  Or I need to go into each new/updated playlist in my collection and re-analyze each new/updated track as well?