Snap package licenses

Neal Gompa ngompa13 at
Tue Jan 31 18:24:44 UTC 2017

SUSE has their own list of non-standard references[1], but my
understanding is that SPDX is working on making this a bit more
flexible in this regard. This was one of the reasons we haven't
switched to it in Fedora (the other being the mismatch of BSD/MIT tags
to SPDX equivalents). AppStream metainfo files shipped with software
include the SPDX license tags[2].

One of the reasons I personally favor the Fedora tags more is because
it's not obnoxious with dealing with classes of licenses. However,
AppStream does mandate SPDX, and harmonizing snap metadata with
AppStream metadata makes it easier to keep things sane and in sync,
especially if developers want to use their metainfo files as input for
generating parts of the snap metadata. Of course, maintaining harmony
does not imply that SPDX license tags need to be used in snap data,
only that some kind of automatic mapping from SPDX to another system
is available. Richard Hughes' appstream-glib (used by GNOME/Ubuntu
Software) has such a mechanism for going from Fedora/SUSE-classic to
SPDX[3], and the other way around is considerably simpler.


On Tue, Jan 31, 2017 at 11:43 AM, Gustavo Niemeyer
<gustavo.niemeyer at> wrote:
> That's an interesting idea.  Is there a known repository for license texts
> which are not standard?  I see SPDX uses a LicenseRef-<ID> kind of
> reference, but it's not clear what that is referencing. Just another field
> inside the XML in the case of AppStream, I suppose?
> On Thu, Jan 26, 2017 at 9:58 PM, Neal Gompa <ngompa13 at> wrote:
>> On Thu, Jan 26, 2017 at 5:35 PM, Mark Shuttleworth <mark at>
>> wrote:
>> >
>> > We should allow a plaintext field there for this situation. Yes, go
>> > ahead with "Other open source".
>> >
>> It would probably make sense to support SPDX license tags and
>> expressions[1]. This is used in AppStream, so a great amount of
>> software is already classified in this manner. Furthermore, openSUSE
>> uses SPDX tags for their license metadata for packages, and Debian
>> uses a subset of it as part of the copyright file structure in Debian
>> Source Control packaging.
>> While we in Fedora use our own license tag list[2] that predates SPDX
>> (used by a great deal of Linux distributions), we maintain a mapping
>> to SPDX for AppStream support.
>> Having verifiable license information (either Fedora style or SPDX
>> style) is also useful for ensuring things are "compatible" or
>> "desired" on a system, depending on whatever preference you may have.
>> [1]:
>> [2]:
>> --
>> 真実はいつも一つ!/ Always, there's only one truth!
>> --
>> Snapcraft mailing list
>> Snapcraft at
>> Modify settings or unsubscribe at:
> --
> gustavo @
> --
> Snapcraft mailing list
> Snapcraft at
> Modify settings or unsubscribe at:

真実はいつも一つ!/ Always, there's only one truth!

More information about the Snapcraft mailing list