Maone said so in https://mailman.boum.org/pipermail/tails-dev/2015-March/008346.html but there is no mention of this on the Tor Browser design document (https://www.torproject.org/projects/torbrowser/design/) which instead mentions that "addon updates" are proxied as well.
#1 Updated by sajolida about 4 years ago
- Status changed from Confirmed to In Progress
#2 Updated by sajolida about 4 years ago
- Status changed from In Progress to Resolved
The answer is no, normal updates are prevented only for Torbutton and Tor Launcher. https://lists.torproject.org/pipermail/tbb-dev/2015-April/000258.html