It is a piano concerto.
Percussion diagrams for piano concertos nowadays aren't that uncommon because percussion sections have expanded significantly, and a lot composers care a lot about spatial organization also. Any other hints about the composer and/or work?
Well, [timp.2perc] with no mallet instrument is fairly weird, so that might be a clue.
Studied with Babbit and Sessions
How is that weird? Not everyone uses mallet percussion instruments nowadays. There isn't really a standard as to how people write for percussion nowadays. People just do whatever they think works in their piece.
While we wait. Here is one by me. I know some people will find it easy, but it is really quite rare when you think about it.
Is no.1 a paraphrase on Bellini Norma? and is no.2 by Arensky?