As I do not think my former message reached gimp-users, I will try there
(it also seems more fit, and I am subscribed):
Is there any way to directly edit the alpha layer of a layer. Layer
masks do only reduce the alpha, never increase it; and sometimes I would
like to somehow delete any opacity information in a layer, without
having to repaint all. So maybe there is a solution, but I didn't find
this (since editing a mask is not the answer)...
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