this issue has been discussed a few times on the forums, so I finally put in a ticket to solve the issue
this would be used for cases where a song wasn’t written or arranged for the target work (i.e. soundtrack, musical, opera, etc.), but was included pretty much as-is, such as the Pulp Fiction or Baby Driver soundtracks (which are largely popular songs), jukebox musicals, and tracks from one game being used in a later game (but not a new arrangement, of course)
to that end, might make sense to make it a subtype of the “part of” relationship
Tarantino films are a good example of the soundtrack being important. And the popular songs that appear in that soundtrack. It would be good to finally get a way to say “this song appeared on this film’s soundtrack”.
Thanks for reminding me of that thread : Classical works, "part of", and Fantasia The confusion some of us non-classical editors hit is part of the problems here I think. A language barrier of terms.
It seems nobody has a problem with this, but it might not have gotten seen by some, so sticking it for a bit. Unless someone has a clear reason not to do this, I’ll add it in a few days.
it’s currently done with “part of”, this is a new relationship “included in”
I’ve seen “part of” used a lot with video game soundtracks too, especially for Pokémon. the Wild Pokemon victory theme, for instance:
(sometimes the collection attribute is used, which I believe isn’t correct either. there’s quite a few more tagged recurring vgm work)
edit: this might be a bad example anyways, as many of these should probably be arrangement works anyways, most of them are distinct enough.
a better example is when Super Smash Bros included the overworld theme from the first Super Mario Bros game as a stage theme without arranging it at all, even emulating the NES sound, like so. (might be a good example to include in the documentation, actually)
As a short summary - if a work is written for the film it will be “part of” the soundtrack work, but if it was written before the film but used in the film it will be “included in” the soundtrack work.
So does that mean a film like Release “The Breakfast Club” by Various Artists - MusicBrainz can now have its headline track “Don’t you forget about me” as “part of” the soundtrack (due to it being written for the film)? Will the “pop songs can’t be in soundtracks” rule be adjusted at the same time? Otherwise it will look at bit odd for that film as “Don’t you forget about me” would still not be allowed to link to a soundtrack work.
I forget, is this an official rule listed anywhere? I mean, I know we don’t generally add pre-existing songs as part of because it looks stupid and it’s misleading, but I don’t think there’s some rule that a pop song wouldn’t be part of a soundtrack if it was written as part of that soundtrack
I have got so lost in the conversation over the years. I am sure I was previously told to not add “pop” songs when bringing up things like The Breakfast Club before. As long as there is now nothing official against it it should mean I can put all those tracks in the above release into “Part of” the Soundtrack. Which makes sense as they are created for the film.
And all the tracks on the Pulp Fiction CD will be “included in” the soundtrack due to them being written before the film.
A question to check. Often the official soundtrack release does not include all the pop\rock songs due to copyright reasons. Or just lack of space.
If we watch a film, and hear a song in the soundtrack, but there are no releases yet out with the full soundtrack, then can we still select “included in” and credit hearing it by ear alone?
Example: 24 Hour Party People - Wikipedia 18 tracks get onto the soundtrack, but there are the same number again not put on an official release. In this example there would be a source to point to that has documented all the music that appears in the soundtrack.
The norm in pop music covers is that we don’t create separate MB Works for nearly any reason. (New lyrics, new melodies, and new non-misattributed writers would be one reason.)
in my opinion, yes, this is exactly what this relationship is intended for
there is an opposite case too, as unless they were also included, tracks from a “music inspired by” soundtrack would likely not get this relationship (or any other soundtrack release tracks that didn’t actually appear in the film or show, unless maybe they were written for it and were cut)
I’d have to give it a closer listen, but the only commonality I hear between all of these (save for Legends Arceus and Scarlet/Violet, obviously) is the melody. the harmonies and rhythm/bass parts are quite different in most of these. a possible exception I heard on a second listen is that Diamond/Pearl and Brilliant Diamond/Shining Pearl do have a similar arrangement (there could be more, I’d have to give it another few listens)
I did a deep dive similar to this about a year ago for Gourmet Race / Dreamland / Fountain of Dreams (depending on the game), which has basically become a main theme of the Kirby series
as to the rest, we might be getting a bit off-topic to this thread, tho I’d be down to discuss it in a new thread. tho I will say I feel that VGM (and soundtracks in general) might be its own thing between popular and classical, too classical to be popular, but also too popular to be classical (or maybe a subcategory of both)
on a similar note, one outstanding question I have is if a cover or arrangement of a piece is made for a soundtrack (or musical or whatnot), should that get a new work and “part of” relationship, or no new work and an “included in” relationship?
one such example is Holding Out For a Hero from Shrek 2. it’s a cover of the Bonnie Tyler song, but in a different style, and it interpolates the heroic theme from the previous movie (you can hear it when Shrek comes riding in on Mongo, the giant gingerbread man)
I think I personally favor creating a new work in cases like the above, where there’s other works interpolated, but for cases where there’s not as significant a change in the music, I’m not sure where I stand
: 
I am sure I was previously told to not add “pop” songs when bringing up things like The Breakfast Club before. As long as there is now nothing official against it it should mean I can put all those tracks in the above release into “Part of” the Soundtrack. Which makes sense as they are created for the film.