[RcouF1uZ4gsC]

One advantage of mercurial is that it is less tied to a specific file format like git is. It is much easier to make a mercurial backend for a system which actually stores the code in a different way (for example a distributed data store).

[Mindless2112]

...or stores it in .git[1].

[1] https://www.mercurial-scm.org/wiki/GitExtension

[klodolph]

Isn’t this also possible with Git, at least for remotes? There are a number of different Git implementations besides the main one.

[alexhutcheson]

There are multiple implementations, but the contents of the .git directory are essentially the API, which tightly constrains how it can be implemented.