It is explained here https://grapheneos.org/usage#web-browsing
They don’t explicitly mention Firefox but:
"Chromium-based browsers like Vanadium provide the strongest sandbox implementation, leagues ahead of the alternatives. "
and
"Chromium has decent exploit mitigations, unlike the available alternatives. "
Since I myself lack the knowledge and skills to judge this, I have to trust the word of the developers.
Edit, correction. They do mention Firefox
“Avoid Gecko-based browsers like Firefox as they’re currently much more vulnerable to exploitation and inherently add a huge amount of attack surface.”














That’s not a autismus thing. Basically everybody has this problem nowadays. https://youtu.be/VYJtb2YXae8