MarsSeed [1] filed a deletion request for bzr-gtk-bzr [2]: Orphaned and broken VCS package. Seems unneeded. Also source development has been discontinued; last commit was in 2016.
There's another AUR package: bzr-gtk, which has a maintainer and is non-VCS. So it is not a loss to anyone if this VCS one gets deleted. [1] https://aur.archlinux.org/account/MarsSeed/ [2] https://aur.archlinux.org/pkgbase/bzr-gtk-bzr/
