MarsSeed [1] filed a deletion request for matrix-puppet-hangouts-git [2]: Terminally broken. Google Hangouts API has been shut down in 2022. (Also the required dependency 'hangups-git' no longer exists due to same reason.)
[1] https://aur.archlinux.org/account/MarsSeed/ [2] https://aur.archlinux.org/pkgbase/matrix-puppet-hangouts-git/
