sed is in the base group and according to https://www.archlinux.de/?page=PackageStatistics present on nearly all systems. I see now that this is a fallacy, as pkgstats requires sed :-P. However, pacman requires curl, which requires ca-certificates, which requires sed :-).

I'll push a commit that I had already prepared locally. Very cool that you noticed this! Do you code bash for your day job?