I guess you know the story with Firefox port in GTK3. Martin Stransky uploaded the binaries on Copr Building System.

Repos are available for Fedora 18, 19, 20 and Rawhide, both for 32& 64bit archs.

Firefox Port in GTK3

Firefox can now use any GTK3 Theme | Adwaita Dark Theme

Martin says:

New builds are available at copr. Package firefox-gtk3-29.0-3 contains working NPAPI plugin support, so flash and other should work there. Please report any issue to bugzila (firefox component) and note it’s the gtk3 port. Thanks!

Installation

Notice that there are many bugs concerning Firefox UI, and this is just a Tech Preview. The good news is that FirefoxGTK3 can work together with your normal Firefox installation, and is safe to install it side by side.

1. Select Fedora Version

Go to: http://copr.fedoraproject.org/coprs/stransky/FirefoxGtk3/ and select your build. Which is the same repo for any Fedora version and any architecture anyway.

2. Create a repo

$ sudo gedit /etc/yum.repos.d/firefox-gtk3.repo

Add the repo info from the above link. In my case (Fedora 20).

[stransky-FirefoxGtk3] name=Copr repo for FirefoxGtk3 owned by stransky description=Firefox built for Gtk3 toolkit. baseurl=http://copr-be.cloud.fedoraproject.org/results/stransky/FirefoxGtk3/fedora-$releasever-$basearch/ skip_if_unavailable=True gpgcheck=0 enabled=1

I am not giving a direct “wget” command to add a repo, just to make sure that you know what are you doing :)

3. Update Repos

$ sudo yum update

4. Install

$ sudo yum install firefox-gtk3

5. Done!

You can start Firefox in GTK3 from Shell Application Overview or from command line.

$ firefox-gtk3

You don’t just have a GTK3 Firefox, you also have the very latest build of Firefox. How cool is this? ;)

Motivation

Why Firefox in GTK3?

GTK3 themes either don’t or can’t implement a GTK2 equivalent and distributions are using these GTK3 themes and so Firefox looks different.

New toolkit features are added to GTK3 but rarely ported to GTK2. This includes support for input events such as touch events and Wayland.

GTK3 provides the option of rendering native widgets to CPU memory surfaces, which would allow Thebes layers to be rendered to these surfaces before being uploaded for compositing.

Besides, GTK2 is pretty much unmaintained with only minor fixes and translation updates, in the past 2 years.

By the way, if you are still on Fedora 18, time to upgrade. Fedora 18 support is over since 14th of January.