aero31aero [1] filed a request to merge bismuth [2] into kwin-bismuth [3]: Both have the same upstream. The other package's PKGBUILD is more arch-like than this one, in that it properly tries to place the files manually/more transparently in the correct folders.
[1] https://aur.archlinux.org/account/aero31aero/ [2] https://aur.archlinux.org/pkgbase/bismuth/ [3] https://aur.archlinux.org/pkgbase/kwin-bismuth/
