How to know the song was made for the media or song that is licensed to used through the credits?

For a long time, I have been an idiot. If I want to know whether the song is made for the media (video games, movies etc) or not, I can check the credits. Which comes to my question, how to check the credits for status of the song.

Does using the term “Courtesy of” signified the fact that the producer licensed to use this song instead of made for the media? Also how do I know that which music is made for the media through the credits?