When you say "it's been around for awhile"... what's the location of
"around"? What I mean is, is there any compilation of these
undocumented-but-true features?

I suspect there's no canonical source... but if you can point me in the
right direction(s) to read more about Excel tricks and techniques, maybe I
can get started in this direction. Or should I just continue to use Google
as my starting place for research into the lore of this secret fraternity?

Thanks.
Eric