Are they losing contributors, though? I like GitHub/Gitlab/BitBucket as much as most people but choice of version control is going to be secondary to getting your patch into a major web browser in my opinion.
Also looks like they're still planning on using existing review tools:
> We will continue to use Bugzilla, moz-phab, Phabricator, and Lando...
Although we'll be hosting the repository on GitHub, our contribution workflow will remain unchanged and we will not be accepting Pull Requests at this time
Lol, only reason I don't mind it is my company's self-hosted instance is extremely snappy compared to SaaS GitHub/Gitlab. But it's getting behind in features. Wish it had multiline comments/suggestions.
I have been quite happy with BitBucket. This is mostly from a UX perspective. The design is clean and simple. I’m using GitLab lately too, and my experience is the opposite. I can’t think of any webapp with a worse UX.
Not using it increases the barrier to entry. Potential contributors are likely to know git and be relatively familiar with the contribution process on Github.
Hosting it elsewhere means people are less likely to find it in the first place.
Using a different VCS means people are less likely to pick it up. Instead of starting on their contribution they have to install and learn new tooling that is irrelevant to the project itself.
Emacs is a pretty good example of this. There are plenty of people who would be interested in making improvements to the project but a much smaller proportion are willing to engage with the email-based process that's required to do so.
The crux of the issue is that the social element of an approach is just as important as the technical merit. A technically superior solution will quickly languish if no one can bear to work on it.
> Hosting it elsewhere means people are less likely to find it in the first place.
But Firefox is a well-known software and, at the same time, a very complex one. I don't think that somebody who struggles figuring out how to contribute via, e.g., Gitlab, will be able to contribute anything useful to the project.
Motivation and visibility is the problem, not ability.
People only have so much time and even insignificant barriers reduce participation.
The Emacs example is a bit more involved but still demonstrates this. There's nothing particularly difficult about submitting patches by email but the thought of doing so does put people off. The same goes for the copyright assignment, not difficult at all but reduces participation.
