List 64-bit Linux Tor Browser first on download pages?
Assumption 1: they don't work if you fetch the wrong one. specifically, I think the 32-bit one does not work on 64-bit systems. I just checked this again and it seems to be true.
Assumption 2 (Karsten or Sebastian can learn whether this is true, e.g. from the same analysis as on #18768 (moved)): The 64-bit bit one is more used, since a lot of people are 64-bit people nowadays.
If both of these assumptions turn out to hold, I think we should list the 64-bit one first.