[China] Sometimes Tor Directory Authorities and built-in bridges are available in some ISPs

Since November 15th, we've seen a sudden increase in direct connections from China on Tor Metrics website. Looking into the OONI data set, some ISPs temporarily and partly unblocked Tor Directory Authorities and built-in bridges, for example, AS4134. In some cases, the ISPs even unblocked Tor completely AS4837, AS17623.