Support foreign language input where possible.
sandboxed-tor-browser sandbox creates new NET and IPC namespace, breaking most foreign language input methods. This will require figuring out how the input method communicates with X and the client app, and writing code to bridge the host system and the firefox sandbox.
Eg: IBus based input methods use D-Bus for communication. Simply allowing host D-Bus access is extremely suboptimal and is not something I'm currently considering.