Binaries (slightly dated) are currently available on Hyperbola Project.

You can see the PKGBUILD here: https://git.hyperbola.info:50100/packages/extra.git/tree/iceweasel-uxp

There is also a Gentoo ebuild here:
https://github.com/g4jc/iceweasel-uxp-overlay

The jest of compiling yourself is:

1. Install dependencies
2. git clone UXP from upstream
3. create application/ directory
4. git clone this iceweasel-uxp.git
5. drop a .mozconfig in there
6. ./mach build && ./mach run or ./mach package.

You can also follow more or less the same instructions as Pale Moon, it has a CentOS dependency list which should be the same for Fedora: https://developer.palemoon.org/build/linux/

Thanks, found a bit confusing. I use Debian and Arch. Do I need to write down all files in Hyperbola with a text editor and then run iceweasel-uxp.desktop?

The desktop files aren't really needed other than for aesthetics in GNOME/Desktop Environment. If you can get ./mach build working you can create a stand alone binary for distribution which you will be able to run from anywhere.

More on .desktop files:
https://wiki.archlinux.org/title/desktop_entries
https://developer-old.gnome.org/integration-guide/stable/desktop-files.html.en

Biggest issue you'll have is that UXP only builds with Python 2 and most distros have removed it so you'd have to find a way to install Tauthon.
https://github.com/naftaliharris/tauthon

Thanks, found a bit confusing. I use Debian and Arch. Do I need to write down all files in Hyperbola with a text editor and then run iceweasel-uxp.desktop?

If you figure out how to build an iceweasel-uxp PKGBUILD, can you share it with me or put it on aur, or something similar so I can build a pkgbuild too? But yeah, use tauthon should work.

Thanks for the detailed instructions. A lot of things have changed for me since I opened this issue.

It seems to me that Iceweasel-UXP is suited specifically for Hyperbola, and its build dependency on a dormant Python 2.7 fork is concerning.

I guess this application isn't very different from Pale Moon, Basilisk Browser, etc., so I suppose I can use them instead if I need to with a few configuration changes...