MarsSeed [1] filed a deletion request for x262-git [2]:

Defunct, currently unbuildable, but also unused library.
Upstream EOL since 9 years ago. [a]

It is pointless to keep this on AUR.

[a]: https://git.videolan.org/?p=x262.git

[1] https://aur.archlinux.org/account/MarsSeed/
[2] https://aur.archlinux.org/pkgbase/x262-git/