All IR music is packed into the bank files, so you won't find them available as flac/mp3 files within the game folder.
To get access to them you will have to unpack the bank files.
The three tracks fra the latest dlc were previously available, but for some reason there were packed together with all the base game tracks in the main bank file.
Now I guess they just moved them to a seperate bank file in the respective dlc folder.
@Jamor, I actually have one question regarding these dlc tracks that maybe you might be able to help me with.
I created a music mod for I:R that I posted recently on the workshop that replaces the I:R music with some custom music.
The main reason I wanted to replace it is that your tracks, for some reason, are significantly more quite than any other music that one adds on top of it, so they just don't play well together with the custom music.
The only problem I encountered is that while I managed to replace all the tracks from the main bank file by unpacking and then recompiling it, that method doesn't seem to work for the dlc banks. I made sure to keep the same folder structure, etc. and the banks recompiled successfully with the custom music, but once I put it in the mod the I:R music from the dlcs still plays instead of my custom tracks.
Do you, by any chance, know why? Any tips would be very much appreciated.