better handling of feat. artists

[UltimateRiff]

featured artists are handled very inconsistently across the various platforms, with Spotify removing feats and putting them in the artist field, Deezer keeping feat in the title and the artist field, and Apple Music only keeping feats in the track title. I think if a service has a featured artist, this should be reflected in the harmonized data, both on the track level and potentially on the release level (if all tracks have the same feat, especially for singles)

here's a decent cross section of the variants on this release

[zas]

In the example shown above, "feat." should be preserved, and not converted to "&" (that's what Spotify does, but that's incorrect).

From my experience, most sources will use "title (feat. B)" by A and only Spotify will use "title" by A & B.
There are often variations for: title feat. X, title (feat. X), title (ft. X), title (with X), etc...
Plus language-related variations, for example a French release might have "title (avec X)" on some platforms, and "title (feat. X)" on others.
Plus capitalization variations.

In the example above, we have 3 sources for most tracks, 2 showing (feat. X) and 1 with raw title, they could be used: Spotify gives a list of artists, others sources list artists in title:

• title by C, A, B
• title (feat. A & B) by C

I would expect we get: title by C feat. A & B when adding this to MB.

We clearly need some heuristics here, and perhaps suggest a set of options in complex cases.

[wileyfoxyx]

I think it depends on label too. Here's a track that still has feat. in it's title in Spotify:

[mr44er]

Another example to play with/test scripts: https://www.deezer.com/es/artist/145401
Two different bands with the same name and Ars Moriendi vs. ars moriendi