Set browser.urlbar.formatting.enabled to false in about:config

Well that's certainly not something most people will ever figure out. Thanks! I'm surprised that there is no checkbox in the 'firefox preferences' for this feature.

I had this problem too (and I've always hated that other browsers did it). Thanks for having the solution!

Yes, thank you for making it possible to disable this.

To be clear, the problem is that the formatting does not actually highlight the domain, but instead fades everything else. I (probably) wouldn't mind having the domain highlighted, but I still need to be able to easily read the rest of the URL, since most of the time I already know the domain and the rest of the URL is the interesting part.

For a future release, please consider only modifying the formatting of the domain (perhaps by making it bold or changing its background color) without hindering the legibility of the rest of the URL.