My go-to reference says of them "edible but can be a little bitter". Given that of others he says things like "edible but not worth it", I guess that means your giant polypore might be tasty and nutritious if you can find a fresh soft specimenThese apparently can be eaten - though nobody has said they are delicious. I haven’t tried.
They are Meripilus giganteus. And giganteus is correct.
If I dared eat them, just one frond would be a meal for two.
They live off dead trees apparently.
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