QUOTE (ShadowMare @ Sep 20 2009, 16:36)

You know, the one you see, when you just play some tracks. Call it working/now playing/temporary - whatever!
This could be any of the playlists found in
%appdata%\foobar2000\playlists (for a typical install)
QUOTE (ShadowMare @ Sep 20 2009, 16:36)

This playlist is not saved by the user, but by fb2k, because it recognizes your last playlist and restores it.
Sure, foobar knows which playlist is being played.
QUOTE (ShadowMare @ Sep 20 2009, 16:36)

Now I need this so called playlist, it has to be anywhere on my disc, but I'm not able to find it.
You're not conceptualizing this correctly, obviously.
QUOTE (ShadowMare @ Sep 20 2009, 16:36)

Can you help me?
Another solution for getting the tracks out of this playlist is good, too

Well, you can get the
SDK and develop a foobar2000 component to save the relevant information in a format and place that is useful and findable by your application.