These extensions are intended for users who live in uncensored areas countriesthat is, countries that do not block access to Tor.
The two extensions convert the browser to a proxy, allowing them users censored countries to connect via the extension (and the user's computer) to the Tor network.
Let's first look at how the Tor network works and how it combats Internet censorship
The Tor network is a set of servers that encrypt the data stream they offer anonymity and keep the users location hidden.
The Tor network has several types of servers: guard servers (network access points), relays (control the flow of data within the network and enhance anonymity) and exit servers (reconnecting with the "normal internet").
The IP addresses of Tor guard servers are public and are located at website of Tor. From there you can connect to the Tor network via a secure server.
The governments of different countries have realized that they can block it access on these servers and thus block access to the Tor network.
In response, Tor Project created another type of server, which is also a guard server, but its IP address is not public. This type of server is called Tor bridge.
Users living in oppressive regimes can connect to the Tor network by requesting through their Tor Browser an IP address of the Tor bridge server.
However, the governments also managed to block Tor bridge servers.
Tor Snowflake is Tor Project's latest effort to help censor users.
Tor Snowflake helps create a constantly moving network of proxies that could not be blocked by anyone government.
When users (non-censored countries) install Chrome or Firefox (Tor Snowflake) extensions, users in countries such as Iran or China can connect to regular Tor bridges via users' browsers.
The more extensions installations, the more proxies available.
Censorship users can easily install Tor Snowflake extensions for Chrome or Firefox.
There is also the ability to simply enable Snowflake (no installation). It is enough to link to the site and keep the tab open.
Regarding users of censored countries, they need to modify the settings network of Tor Browser and click on the option, shown in the picture below:
The downside of Tor Snowflake is that someone else uses it browser and exploits your bandwidth.
The Tor Snowflake project was started by 2016.
This summer, however, Tor developers released the two extensions, which are now available for Windows systems as well.