What determines that?
Usually a judge, But I’ll give my opinion about 3 seform I have nearby:
Artscroll Interlinear Siddur – IP in layout (That’s my interpertation of the law, personally I’d leave out the “I” in “IP”)
Oz VeHehadar Gemorah – IP in layout, but most of it is already in the public domain (being newly typeset has no affect)
Beis HaLevi (Mishor) – No IP in layout