(In reply to Clemens Eisserer from comment #1)
In times where emscripten and wasm perform so well, wouldn't it be better to replace pdf.js with poppler compiler to wasm? PDF seems to cause tons of troubles and maintenance costs - wouldn't it be better to have the pdf.js team join firefox again, instead of burning ressources for even mroe years?
Let's leave this bug for discussion about the annotation bug, but this has been considered and it is much more work than it appears to switch.
Maybe you have some thoughts on why the annotation isn't working?