MarsSeed [1] filed a deletion request for parallel-rust [2]: Unused rewrite, discontinued since 2017, of extra repo's parallel (which is on the 2023-09-22 release version atm). Also conflicts with the repo package. I don't think it's useful to keep.
[1] https://aur.archlinux.org/account/MarsSeed/ [2] https://aur.archlinux.org/pkgbase/parallel-rust/
