https://www.aseprite.org/, looks like a really nice pixel art editor / sprite editor.
The author needs to eat, therefore relicense (I think).
It seems like this is the crux of the matter: https://dev.aseprite.org/2016/09/01/new-source-code-license/ and https://github.com/aseprite/aseprite/issues/1666 https://github.com/aseprite/aseprite#license