Comment # 6 on bug 1185613 from Petr Gajdos

(In reply to Ludwig Nussel from comment #3)
> Yes and no. You can't do this during build time:
> 
> $ osc rbl openSUSE:Factory groff standard x86_64|grep -B2 -A4 "++ PRETTY_NA"
> [   64s] + . /etc/os-release
> [   64s] ++ NAME='openSUSE Dummy'

Speaking with the same language

$ osc rbl M17N groff openSUSE_Tumbleweed x86_64 | grep -B2 -A4 "++ PRETTY_NA"
[   49s] ++ ID_LIKE='opensuse suse'
[   49s] ++ VERSION_ID=20221217
[   49s] ++ PRETTY_NAME='openSUSE Tumbleweed'
[   49s] ++ ANSI_COLOR='0;32'
[   49s] ++ CPE_NAME=cpe:/o:opensuse:tumbleweed:20221217
[   49s] ++ BUG_REPORT_URL=https://bugs.opensuse.org
[   49s] ++ HOME_URL=https://www.opensuse.org/
$

I guess it will be safer to hardcode it then and be done:

(In reply to Dr. Werner Fink from comment #4)
>  vendor=OpenBuildService
>  %if 0%{?suse_version} > 0
>  %if !0%{?is_opensuse}
>  vendor=SLES
>  %else
>  vendor=openSUSE
>  %endif
>  %endif