xduugu [1] filed a deletion request for rsyncbtrfs [2]: Seems to be an old version of rsbtbackup[1]. At least the upstream url points to the same github repository.
[1] https://aur.archlinux.org/packages/rsbtbackup/ [1] https://aur.archlinux.org/account/xduugu/ [2] https://aur.archlinux.org/pkgbase/rsyncbtrfs/
