https://phabricator.wikimedia.org/transactions/editengine/maniphest.task/view/82/ links to https://www.mediawiki.org/wiki/Requests_for_comment which is obsolete.
The form seems to be only linked from https://www.mediawiki.org/wiki/Requests_for_comment#Create_an_RFC (and not from https://phabricator.wikimedia.org/project/profile/52/ ).
Could not find any information on https://www.mediawiki.org/wiki/Technical_Decision_Making_Process .
(For the records, I already boldly disabled Form 89 which seemed to be a copy of Form 82 (and I'm unable to find out where to see its author.)