firefox 79 issue w/ spdy in about:config

[Gary Aitken]

search (using chrome and duckduckgo) didn't come up with anything recent so
I'm a bit puzzled...

I recently had to pkg remove mysql 5.7 to dump and then install 5.7 back; the
result was a bunch of upgrades, including firefox from version 77 to 79.

When firefox was restarted, almost no sites worked, including duckduckgo.
The recommended solution, from back in 2016, was to set
   network.http.spdy.enabled.http2=false

That solved the issue, but I'd like to understand what's going on.
Since ff was working prior to this upgrade, and I don't *think* I set the above
config option to true...  and since true is the default... can anyone tell me
what's going on?

Mostly clueless, thanks,

Gary