When the decision was made to use Mercurial, Git for Windows wasn't a viable option. If you wanted to develop on Windows, the choices were Mercurial or SVN. Ed

When the decision was made to use Mercurial, Git for Windows wasn't a viable option. If you wanted to develop on Windows, the choices were Mercurial or SVN. Edit: I work for Mozilla, although I didn't in 2006 when I think the decision was made.