That's ash, as in "A SHell", namely /bin/sh...

I'm wondering if there is a place I should look for the mostest recentest
version. :)

More generally, if there's a good way to find out such information for
other contributed programs.

More specifically, I'd like to add a "type" builtin and just maybe     
a pattern matching builtin or two ("case" doesn't count :).
I'd also like to fix whatever bug it is that seems to bomb out in
large case statements of GNU autoconf scripts -- I may need to
poke around in the NCASE/narg structure a bit.