WorMzy [1] filed a deletion request for picom-tryone-git [2]:

Misnamed duplicate of https://aur.archlinux.org/packages/compton-
tryone-git/

[1] https://aur.archlinux.org/account/WorMzy/
[2] https://aur.archlinux.org/pkgbase/picom-tryone-git/

My mistake, this is pulling from a different branch to the compton-
tryone-git package, which has renamed to picom.