You can click on the uBlock icon and open the logger (little icon that looks like a window with lines) to see which requests are being blocked. I'm seeing xhr'

You can click on the uBlock icon and open the logger (little icon that looks like a window with lines) to see which requests are being blocked. I'm seeing xhr's to https://collector-medium.lightstep.com/api/v0/reports https://collector-medium.lightstep.com/api/v0/reports being blocked every few seconds. Probably some medium analytics request.