In my tumbleweed install there is a file `/etc/SUSE-brand` but no `/etc/SuSE-release`. The latter is used by python 2.7 at least to identify the distribution python is running on. For example:
$ python
Python 2.7.12 (default, Jun 28 2016, 06:57:42) [GCC] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import platform
>>> platform.linux_distribution()
('', '', '')

If I link SUSE-brand to SuSE-release:
$  python
Python 2.7.12 (default, Jun 28 2016, 06:57:42) [GCC] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import platform
>>> platform.linux_distribution()
('SuSE', 'openSUSE', '')

This is important for software like cobbler (for which there is a rpm in tumbleweed, did anyone even test that it could be started?), which relies on this particular call as well as the SuSE-release file presence to identify the right default for the service (such as what is the apache2 user).