Hello! Adonay is right that the project’s channels are not the place to discuss third-party channels and distribution methods, especially channels and tools that provide non-FSDG-compliant software.
As for Firefox, it pops up every now and then, but there seems to be a lasting misunderstanding. Firefox, as is, will not go into Guix because it does not comply with several items of the FSDG, which the project is committed to following (for example, by linking to Mozilla’s add-on catalog, which contains non-free software.) However, a version of Firefox stripped from the bits that make it non-FSDG-compliant would be welcome. This is essentially what IceCat is about, but IceCat is based on an LTS version (I think that’s what you meant by “old”) and it enables various privacy-enhancing plugins by default. I think there were a few attempts to do that in the past, but they were not completed, so we’re having this discussion again. :-) It might be that the “clean up” code we have for IceCat would work with few modifications on the latest Firefox. I hope this clarifies the situation! Until then, happy web browsing. :-) Ludo’.