The "protobuf" package in 13.1, 13.2 and Factory all have a python binding
package (python-protobuf).

It is not present in Leap and is preventing at least one app in OBS from
working on Leap (python-plaso).

The reason seems to be error in the Leap protobuf specfile.  It has:

==
%if 0%{?suse_version} > 1210 && 0%{?suse_version} != 1315
%bcond_without protobuf_python
%else
%bcond_with protobuf_python
%endif
==

Note that SLES 12 (suse_version 1315) is not differentiated from Leap in the
above.

The protobuf specfile in Factory has been updated to correct that.  It has:

==
# Don't build the python bindings in SLE12 or old distros
%if ( 0%{?suse_version} == 1315 && !0%{?is_opensuse} ) ||
0%{?suse_version} < 1210
%bcond_with protobuf_python
%else
%bcond_without protobuf_python
%endif
==

Pushing that specfile change to Leap would make python-protobuf available for
any consumers of that API.