Most people get on the Tor network by downloading the Tor Browser and connecting to a relay. But some countries, such as Iran and Russia, block direct access to the Tor network. In those countries people have to use what are known as “Tor Bridges” to circumvent national firewalls. Tens of thousands of people use bridges regularly to circumvent censorship and national or regional restrictions.
https://www.eff.org/deeplinks/2022/10/snowflake-makes-it-easy-anyone-fight-censorship
archive: https://archive.ph/5a6qi