Forking a project, and adding features and removing pulls that you don't want and/or need is kinda the idea behind the whole 'open source' thing.. cause what else would you do with the source code, but compile it.
Speaking of Firefox, a build or two ago, without warning, Firefox deprecated (broke) every add-on. Because [insert-old-architecture-security-justification]. It's not like anybody was doing anything real with a browser anyway.