Other than https://wiki.archlinux.org/index.php?title=Multiboot_USB_drive&oldid=479923 there is no page documenting how to create multiboot usb drive that boots everywhere (libreboot/bios/uefi/whatnot-where-grub-was-ported). And since libreboot uses grub (where possible) it's the only place how to boot live/install images on libreboot
Why does https://wiki.archlinux.org/index.php?title=Multiboot_USB_drive&oldid=479923 not suffice?
Because it's a historical entry and thus we can't extend it anymore
I see. Perhaps a solution is to link to it on the Libreboot docs and write changes we would like to see on the page on which the instructions are linked?
Solution is written in issue opening comment already -.-