Possible Tor block in Belarus in October 2020

While I was looking at the recent shift in bridge users, I noticed a case of apparent Tor blocking in Belarus on about 2020-10-13 that I don’t think has been previously discussed. There was a sudden, one-day drop in direct relay users (users not using a pluggable transport, just connecting to public Tor relays), and a simultaneous increase in obfs4 users. This is a commonly observed effect: direct Tor blocking causes people to enable pluggable transports.