Based on our record, ImageGlass seems to be a lot more popular than UFRaw. While we know about 41 links to ImageGlass, we've tracked only 1 mention of UFRaw. We are tracking product recommendations and mentions on various public social media platforms and blogs. They can help you identify which product is more popular and what people think of it.
Why not just use https://www.rawtherapee.com/ or https://www.darktable.org/ to process raw files? You can still export from these as .xcf or tiff for further work in gimp if you like. Otherwise ufraw can be used as a plugin http://ufraw.sourceforge.net/ Https://digital-photography-school.com/opening-raw-images-in-gimp-with-ufraw-for-windows-the-basics/ (you mention "are only on linux" but don't mention your OS. Source: over 2 years ago
A GPLv3 similar app, very useful, is ImageGlass: https://imageglass.org. - Source: Hacker News / 2 months ago
If you want to be harassed with updates, check out https://imageglass.org/. Source: about 1 year ago
Stuff like 7zip, eso, shutup 10, klite codec pack, imaglass, a portable notepad++, one commander file manager and stuff. Source: about 1 year ago
ImageGlass, my recommended image viewer, supports HEIC images. Source: about 1 year ago
Checking the internet? Just download ImageGlass and make that one your default image viewer. The same for videos, just grab VLC. Source: about 1 year ago
Darktable - darktable is an open source photography workflow application and raw developer.
IrfanView - IrfanView ... one of the most popular viewers worldwide.
airnef - Wireless download from your Nikon Camera!
FastStone Image Viewer - FastStone Image Viewer is a fast, stable, user-friendly image browser, converter and editor.
RawTherapee - RawTherapee is a free RAW converter and digital photo processing software.
XnView MP - XnView is a free software that allows you to view, resize and edit your images. It supports more than 500 different formats!