Due to an influx of spam, we have had to temporarily disable account registrations. Please write an email to accountsupport@archlinux.org, with your desired username, if you want to get access. Sorry for the inconvenience.
"rescue/installation actions for {grub,refind} should be run from within a chroot" is a false statement. See --boot-directory of grub-install and --root of refind-install. (In the case of grub, there are people that do not use the ugly grub-mkconfig at all.)