Someone posted it to their bug tracker forever ago, with images, but they changed the name to some random unrelated feature request and now I can’t find it. Did find this Bluesky post about it, though:
https://bsky.app/profile/paynamia.bsky.social/post/3kt6odnfbcc2i
You ain’t even getting it doing that. There’s been a bug since 2.10 with transparency. Export anything and you get a crushed alpha channel. Import it into anything else and the alpha looks crazy high contrast. Import it into GIMP again and the contrast is normal, but the channel is still crushed, so it’s banded as fuck.
They say it’s intended behavior, which would make sense if GIMP was a dedicated image corruptor.
To be fair, I didn’t notice it and start digging looking up information about it until I was working on a mod for Half-Life (usually my profile pic, but I think I don’t have it here), and needed to be able to create an extremely specific alpha channel for the phong mask.
Iirc, I experimented with the color profile settings and got no difference. I will say that I can’t seem to reproduce what I was saying about the banding now. For a short while after 3’s release, I was getting major banding in the alpha channel, but now I’m not.