Just a note: .git/refs/snap/ is not standard

Linus, 

    not that there is any "de facto" or any standard there, but
the name .git/refs/snap/ you lifted from the vicinity thing is
not something Cogito folks have.  My understanding is of their
concensus is that .git/refs have single level subdirectories
like 'heads' and 'tags', and there will be little 41-byte text
files that look like .git/HEAD.  So you probably would want to
either (1) readdir in .git/refs (to future proof) or (2) drop
refs/snap from the vicinity list for now (to not give special
treatment to JIT, which I myself do not mind ;-)).  Also if you
go route (2) drop "refs" itself as well.