I have looked for these canon endings and have not found them - where are they established and how far back do they go? Do FO3 and NV have canon endings?
Thanks!
The "Canon Ending" would be established by the next game(s). The original Fallouts and New Vegas have ending slides that would tell us the outcome of our actions. So when you play Fallout 2 which takes place after Fallout you can see what ending slides of Fallout ended up being the canon ones. An example is that The Master from Fallout was indeed destroyed.
Do Fallout 3 and New Vegas have canon endings? Well Fallout 3 has a canon ending and that is the Enclave were destroyed. We know this because the Brotherhood in Fallout 4 tells us things. Things such as using Adam's Air Force Base as their own base. Which they took over after the destroyed the Enclave. We also know that Liberty Prime was destroyed in Fallout 3.
New Vegas we don't have any information yet on which ending from that is canon. Same for Fallout Tactics.