Sounds like a lot of assistive technologies are broken and don’t support basic HTML5 semantics. While there may be a need to do hacks to accommodate this for some time, the right solution is to advocate for them getting fixed.
This was exactly my thought reading this. It isn’t that the assistive technologies are doing something reasonable that doesn’t work well for this use case, it is that these tools are just failing to do anything reasonable for this element at all.
My reading is that it would be better if they just read the full contents if they aren’t providing a way to open the details element. But what they do now is definitely not good.
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