Other than the material in Manual of the Planes, is there a more exhaustive treatment of the Abyss anywhere in the various 3E products. In particular, I'm looking to see if the Plains of Gallenshu (377th layer) have been ported over. I'm aware of the PLANESCAPE information on Gallenshu in Planes of Chaos, but as that is 2E, I am hoping someone can point me to a 3E source.
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There isn't a 3rd ed source.
2nd ed is it.