At 2023-06-29T09:47:50+1000, Greg 'groggy' Lehey wrote:
> There's also grog (groff guess) that may help.  It's not very clever,
> but it recognizes a number of formats:
> 
>  $ grog ls.1
>  groff -mdoc ls.1

I won't claim that grog is more clever now, but as of groff 1.23.0 it
is[1] avowedly less buggy.  It is also 52% of its former size (by `wc
-l`), has 14 bug fixes since groff 1.22.4 (with only a wish list item
remaining), sports an automated test suite, and the tool itself can now
be conveniently passed around as a single file--so I'm attaching it.

Regards,
Branden

[1] Will be.  We're up to release candidate 4 now.

    https://alpha.gnu.org/gnu/groff/