> Gecko doesn't have a WebView implementation (GeckoView is not a WebView implementation), so it has to be used alongside the Chromium-based WebView rather than instead of Chromium, which means having the remote attack surface of two separate browser engines instead of only one. Firefox/Gecko also bypass or cripple a fair bit of the upstream and GrapheneOS hardening work for apps. Worst of all, Firefox does not have internal sandboxing on Android.

> The sandbox has been gradually improving on the desktop but it isn't happening for their Android browser yet.

Context is definitely interesting to have with your statement (From https://grapheneos.org/usage).