I often download different available multitracks to songs to see the way the tracks of the song sound separately. I was wondering if there is a file format that is an undrendered audio format with layers that contain tracks that when being played all together sound as a full mix but which if you open contains in it all the tracks separately. The effects can either be separate or mixed into the tracks. If such a format doesn't exist is it possible to make one and what problems would we stumble upon?
Isn't this generally called a "stem export"? Though usually you get one file per track I think, with the tracks padded to a common starting point in order to preserve their relative timing.
A complete DAW project file (as opposed to one with relative links) will have all the "layers" or tracks and all the transformation actions as separate items, so that you can play or modify any single one at a time if you want.
Or you can open up multitrack recordings with a DAW and modify a particular track if you want.
These appear to both do exactly what you need, at slightly different levels.