The $HomeMovie video encoding format was quite MGR specific, and designed to run on a Sun 2/120 over a 14.k-baud modem (for typical MGR windows) in real-time; it was possible to transfer MGR sessions to remote workstations.
Nice article, by the way.
One thing this article, which is very thorough, and very good, doesn't mention is that all the signalling is in-band via control/escape sequences. Mgr had no analog to xterm. You telent'ed in to some other machine, your shell script did some control sequences, and presto, a new window with a shell on the remote machine showed up.
I believe this article touches on mouse button use. I think Stephen Uhler, the major author of mgr, was left handed, as the default button arrangement definitely was more ergonomic for your left hand.
I had no idea that the author was left-handed; it would be interesting to try MGR with remapped mouse controls, I suppose!
I think I got mgr source off a free software CD, maybe Walnut Creek brand. I did have to fiddle to get it compiled and working.
https://archive.org/details/Source_Code_CD-ROM_Walnut_Creek_...
I can't find an overall mgr version, that seems to not have been a concept. The entire distribution is on 61 "shar" files, which can be undone even today, 37 years after the code appeared on Usenet:
SOME NOTES ON THE DISTRIBUTION OF MGR AS DONE THROUGH THE USENET NEWSGROUP COMP.SOURCES.UNIX
--Rich $alz, Thu Nov 17 20:59:01 EST 1988
This is the largest posting to ever appear in comp.sources.unix;
I think it's worth it. Stephen has been very patient about getting
this out. .....