Snowflake for Chrome and Firefox is a WebRTC pluggable transport for Tor.
If you are a user in a censored country who wishes to connect to Tor, you should download Tor Browser. This extension/add-on is for those who would like to volunteer to proxy users to the Tor network.
What Snowflake does is allows you to share access to free and open communication on the Internet with censored Internet users from around the world. By enabling this extension, you turn your browser into a proxy that connects Tor users in censored regions to the Tor network. Clients will make WebRTC connections to your browser, which will then proxy information between them and the default Snowflake bridge.
Also, no need for concern about which websites the clients are accessing through your proxy. Their visible browsing IP address will match their Tor exit node, not yours.