According to this blog post: Kiln now supports repositories accessible from both Git and Mercurial
We decided that the awesome way would be to make Kiln fully bilingual. It stores every repo in both formats. It automatically converts everything back and forth, always. The translation is 1:1, reversible, and round-trippable. Whatever you do to a Kiln repository using Git will be immediately visible to Mercurial users and vice versa.
I can't imagine that everything runs smoothly. What limitations does this have?