I wanna add one more thing to this list and it's the difficulty of adding bridges. Which is why we increased the number of default obfs4 bridges but I just quickly checked the live stats of mine and they're all under heavy load both traffic wise and CPU. tor is usually at 90% on each instance with avg ~200 Mbit/s traffic.
If this is what all other default bridge operators are seeing, then we're supplying way below the demand. Probably making some censored users unhappy.
They might think it's their adversary who's gotten more advanced in blocking that is throttling obfs4 traffic - which might be the case - and we have no way to measure it.
I don't know what are the plans for the long term approach, but for short term, I suppose we should encourage people who can run some secure, high speed and reliable obfs4 bridges, to do so and have it added to the Tor Browser and Orbot. Especially if they're trusted by the community.
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