Less than 1 MiB/second with GIthub

This is a problem that just started happening for me in the last month or two - it seems to be the same thing as this person reported - though my connection is only 400Mib/second, I'm still getting 1/100th of the speed I expect.
‎GitHub Maxes Out at 1Mb/sec on 1G Connection | Xfinity Community Forum

But there were no solutions posted in that thread.

It's very inconvenient for working from home.