This isn't a "New Feature" request, but I can't select anything else - sorry for that.

Description:

Whenever a user has no skin but does have a cape,

http://skins.minecraft.net/MinecraftSkins/<username>

redirects to the cape instead of returning a 404.

For users with no skin and no cape, a 404 is returned.
For users with a skin, it redirects to the proper skin texture.

Reproducing

Find a player that has no skin but still has a cape.

I know that I can get the proper skin (i.e. no skin) when I know the UUID, but we're using skins.minecraft.net to avoid additional HTTP requests

I also posted some details and a possible explanation of the bug here: https://github.com/Jake0oo0/crafatar/issues/44