Why is this a fork, and not a PR into the main repository?

[colonelpanic8]

This sort of fragmentation is not helpful IMO

[unai-ndz]

Code quality, compiler warnings, etc. Maybe even a rewrite should be done. Merging this as is would be too much of a burden for the main dev.

[darkelectron]

There's a discussion in the main repo: https://github.com/yshui/picom/issues/217