Copy GRUB config from the Debian install to the current Arch live system
Install the up-to-date GRUB while in the Arch environment
The bootloader installer package is distro dependent, the bootloader the package installs isn't. You can boot Debian no matter if the GRUB is installed from Debian stable, Debian Sid, Arch, Fedora or even FreeBSD. Otherwise, dual booting wouldn't work.
Like I said, I've done that before, though with SystemD Boot instead of GRUB, which was a bit simpler due to how the bootloader is configured.
As it's a bootloader, it should make almost no difference which distribution was used to install it. (I'm not sure if Debian patches their GRUB.) I just used Arch as an example, as it is famous for being up to date. And, no matter where it's installed from, if you've made changes to GRUB's configuration, you'll have to copy it over to the live distribution to keep your changes.
Yes, Debian Sid might be more familiar for Debian users, but that's it.
Edit:
You said "get the grub debs from Debian sid", but installing Sid packages on non-Sid systems isn't something that you should do.
But bootloaders are distro/OS agnostic. Why wait for Debian, when you could, for example, boot an Arch live ISO to install a newer GRUB?
I don't use GRUB, but have done the same thing with SystemD Boot before. As GRUB's configuration system is a bit more complex, you might have to mount your main install to get the correct config file.
So, the game would have to be (A)GPLv3. (The licenses are fairly interoperable. IIRC you can use AGPL components in GPL software if you abide by the terms of the AGPL.)
Viral licenses are nice and all, but they're not without their drawbacks. I caught GPL recently (the slightly rarer Affero v3 strain) and now no DNA testing companies want me as a customer. I can no longer write MIT or BSD licensed code. Whenever I open a project, a LICENSE file appears within ~15 minutes of contact. I hope to recover soon.
Just remember that if your shebang points to sh, you can't rely on bash-specific features. The shebang line basically tells the kernel to run your file with the specified program. So, for example, a file with #!/bin/cat will print the full contents of the file (including the shebang) and #!/bin/echo will print the command line. (something like ./script arg1 arg2) As the echo command does not try to interpret arguments as paths, the content of the script would be ignored in that case.
I've read that Xlibre is a fork of Xorg that would still get new features, so I did not know much about it. I use Wayland, as it works better for me, but after reading the readme, I somehow want to use it even less.
This fork was necessary since toxic elements within Xorg projects, moles from BigTech, are boycotting any substantial work on Xorg, in order to destroy the project, to eliminate competition of their own products. Classic "embrace, extend, extinguish" tactics.
How is it EEE? A point about embracing could be made, but wouldn't there have to be extension with non-FOSS code or difficult to implement additions to standards? Even then, as it's hosted on GitHub of all places, it doesn't seem to be that extinguished.
Right after journalists first began covering the planned fork Xlibre, on June 6th 2025, Redhat employees started a purge on the Xlibre founder's GitLab account on freedesktop.org: deleted the git repo, tickets, merge requests, etc, and so fired the shot that the whole world heard.
I haven't heard about this, but I would guess that it's from a CoC violation, based on the rest of the readme.
This is an independent project, not at all affiliated with BigTech or any of their subsidiaries or tax evasion tools, nor any political activists groups, state actors, etc. It's explicitly free of any "DEI" or similar discriminatory policies. Anybody who's treating others nicely is welcomed.
Calling DEI discriminatory is never a good sign.
Together we'll make X great again!
This seems pretty close to a certain right-wing slogan from the USA. I don't know if it's accidental or a joke, but I don't think that it's appropriate, and like the author, I don't have much good faith left for this.
A lot of commits by the Xlibre developer were reverted upstream and the readme does not look professional.
They're on the feddit.uk instance, so it's more likely that they're British. Either their VPN prefers USA servers for some reason, or they've only done about 138 million downloads at most.
I meant the following:
The bootloader installer package is distro dependent, the bootloader the package installs isn't. You can boot Debian no matter if the GRUB is installed from Debian stable, Debian Sid, Arch, Fedora or even FreeBSD. Otherwise, dual booting wouldn't work.
Like I said, I've done that before, though with SystemD Boot instead of GRUB, which was a bit simpler due to how the bootloader is configured.