I've just update my Firefox to the 43.0-6.1 version from the testing channel:
http://download.opensuse.org/update/leap/42.1-test/

panos:~ # zypper patch
Loading repository data...
Reading installed packages...
Resolving package dependencies...

The following NEW patch is going to be installed:
  4425

The following application is going to be REMOVED:
  Firefox

The following package is going to be upgraded:
  MozillaFirefox

1 package to upgrade.
Overall download size: 42.7 MiB. Already cached: 0 B. After the operation,
additional 3.1 MiB will be used.
Continue? [y/n/? shows all options] (y): y
Retrieving package MozillaFirefox-43.0-6.1.x86_64                              
                                                                               
              (1/1),  42.7 MiB ( 99.1 MiB unpacked)
Retrieving: MozillaFirefox-43.0-6.1.x86_64.rpm ..............[done (5.4 MiB/s)]
Checking for file conflicts:
.............................................................[done]
(1/1) Installing: MozillaFirefox-43.0-6.1
.............................................................[done]

Additional rpm output:
Unknown media type in type 'all/all'      <---- Is this ok ?
Unknown media type in type 'all/allfiles' <---- Is this ok ?


Now open Firefox and go to gmail.com it will crash after 5 seconds or so.