1093i3511 [1] filed a deletion request for prerex [2]: All the sources doesn't resolve, upstream isn't reachable. No updates / adoption of the package since 11/2019.
Technically though, this latex package is still available via ctan [1] https://aur.archlinux.org/account/1093i3511/ [2] https://aur.archlinux.org/pkgbase/prerex/
