Non official way to know repo path
In hgext-loggingmod
and in future hg-git
or specific heptapod extension (see hg-git!7 (merged)), we're relying on non-standard way to access the repo root, remarked by @lothiraldan in https://dev.heptapod.net/heptapod/hg-git/merge_requests/17#note_1301
It'd be better to submit upstream a standard API for that and use it.