The ksh source code at
https://github.com/att/ast/tree/master/src/cmd/ksh93
contains files ending with the .mm
suffix.
E.g., https://github.com/att/ast/blob/master/src/cmd/ksh93/PROMO.mm
At first glance, they look like man files but man
doesn't view them well.
How can I view these files in some nicely readable form?