From: Richard Stallman
Subject: Changing font size
Date: Tue, 22 Aug **2017**
“It would be very nice to give Emacs commands to make the font bigger and smaller.”
― https://lists.gnu.org/archive/html/emacs-devel/2017-08/msg00497.html
What you're referring to as Mastodon, is in fact, GNU social/Mastodon, or as I've recently taken to calling it, GNU social plus Mastodon.