mask-mode is a way to composite different masking layers with each other. WebKit currently supports -webkit-mask-composite with all compositing operators. mask-mode is a subset of -webkit-mask-composite with different keywords. It should be easy to support mask-mode.
mask-composite is defined at https://drafts.fxtf.org/css-masking-1/#the-mask-composite. Sebastian
This bug doesn't seem actionable anymore, mask-mode & mask-composite are both implemented. https://commits.webkit.org/245035@main https://commits.webkit.org/25730@main
*** This bug has been marked as a duplicate of bug 229082 ***