What song plays when Kaguya asks Lelouch "what are you really after?" at the UFN meeting at Ashford in 22nd episode of season 2, at timemark 16:10?
I found it finally, it's called Birthplace and I found it after a long time of unsuccessful consumption of code geass music. I decided to, perhaps ironically, attempt to look it up by looking at the names at the Code Geass Wiki, in hopes what a theme of the title will match the required song. It's not on youtube, so I could not possibly have known of it's existense before, and I did relatively less research on other sites, the wiki helped here.
The moment I was looking for actually begins at 0:22 second timemark if you listen to the OST, unexpectedly. It's actually the same song that plays before and after the marked scene, when UFN member discuss whether they were right in trapping Lelouch in the walls, and when Lelouch asks Kaguya what is the most important trait for governing the world. It's one of these "composite" Code Geass OSTs