How and where to report documentation problems????

I recently found a documentation problem.
Essentially a woefully out of date html and pdf feature document.  Confirmed with an active developer who definitely knows.

How and where should I report the problem ???

Well you could start here or/and add an issue in linuxcnc's github issue tracker.

Be advised docs system are being worked on in master and has some growing pains.

I'll fill it in here, and look into the github issue tracker