[License-review] For Approval: License Zero Reciprocal Public License

[Florian Weimer]

* Kyle Mitchell:

>> Clause 4 seems to restrict the use (running) of the software to
>> open-source development.  This is pretty close to a restriction on
>> fields of endeavor.  Even the most restrictive open source licenses
>> (like a common interpretation of the Sleeypcat license, or the QPL)
>> permit arbitrary use for your own internal purpose.  From a practical
>> point of view, this is very important because it allows you to avoid
>> complex license management for purely internal applications.
>
> OSD criterion 6 has come up a few times.  Recapping my part
> in those discussions:
>
> If development of proprietary software is a "field of
> endeavor" against which Open Source licenses cannot
> discriminate, then distribution-triggered copyleft
> conditions like GPL's would fail the criterion, too.  That's
> clearly not the case.  So "field of endeavor" must mean
> something else.

For this reason, I assumed that “field of endeavor” always referred to
activities which do not involve the creation of derivative works.  So
“you may incorporate this program into open-source software only” is
acceptable, but “you may use this program to write open-source
software only” is not, because it disallows writing poetry with the
program.