Re: Help converting Fedora license IDs to SPDX format

J Lovejoy

Hi Richard (x2)!

Richard H - great to hear you are using the SPDX License List for identifying licenses in AppStream for a number of reasons. Your responses below are all correct in terms of understanding the SPDX License List, so I’ll only add a bit more info in regards to the issues you have come across.

As Phil mentioned in his response, the SPDX legal team is currently working through the Fedora Good License list ( in order to identify where the SPDX License List is missing a license that is on the Fedora list. The inclination is to add any such licenses and try to align the SPDX short identifier with whatever Fedora had been using. However, for the reasons you and Richard F identified (e.g. I’ll call it the “MIT bucket,” identifying that Fedora uses to describe similar licenses) not all the short identifiers will align. I suspect we will end up with a “equivalency” document as part of the SPDX License List reference materials, for convenience. In any case, the next release of the SPDX License List is currently schedule to coincide with the release of 2.0 of the spec, so at that point you will see many additions to this end.

In regards to the exceptions, this is also something we are currently working on. As of 2.0, license exceptions will be treated as a modifier to the base license to better enable capturing the various exceptions that exist in the wild. An explanation of this change, as well as the bigger picture in regards to creating a better way to express complex licensing info for files was recently summarized here:

If you are not on the legal mailing list, please join!! (

<<I have responded to both the general and legal mailing lists here, but subsequent discussion should move to the legal list only, where it will get more direct responses/discussion :)



SPDX Legal Team co-lead

On May 2, 2014, at 8:03 AM, Richard Hughes <hughsient@...> wrote:

On 2 May 2014 14:41, Richard Fontana <rfontana@...> wrote:
Also (based on what little documentation on AppStream that I looked at) it is unclear what the purposes are in the case of AppStream.
So, for AppStream the idea is to explain the licenses in the
user-facing software center, e.g. gnome-software or apper for KDE.
This would mean you could click on a link that says "GPLv3+" and get
sent to rather than just having a
license string to look at and perhaps Google.

My knowledge of SPDX itself is limited, but if you look at: you will see
that SPDX is using license identifiers in an entirely different way
from how Fedora uses RPM metadata license identifiers.
Right. The idea is that you can define "upstream" what licenses your
software is using, rather than relying on the packager to work it out
and apply broad classification during the packaging step. I'm really
only doing this for applications not explicitly specifying what SPDX
licences they are using.

A good example, though not on your list probably because you assume it
is not problematic, is "MIT". For SPDX, this means subject to the points made in
the SPDX matching guidelines.

For Fedora, however, "MIT" is supposed
to mean a wide range of different license texts (which SPDX would
surely treat as distinct, non-matching licenses) that were determined
by the Fedora Project to be what I myself might verbosely call "X
Window Project-descended license family licenses, particularly as
distinguished from BSD-family licenses" if I had to call it anything.
Yes, this is the fudge-factor I was talking about. Ideally we would
have all these MIT-variants as separate SPDX license IDs.

So for the ones you list, first of all for most of these there isn't
any SPDX license identifier anyway even if you ignore the issue I just
talked about, since the SPDX list is, at least at present, not meant
to be a comprehensive list of all licenses ever encountered in, say, a
conventional Linux distribution, but rather those that are "commonly
found". In your list, none of those are "commonly found" in that sense
except that the AGPLv3 part of "AGPLv3 with exceptions" is *likely* to
correspond to SPDX AGPL-3.0, but not the "with exceptions" part which
has no SPDX license identifier counterpart.

(By contrast there are
some GPLv2 and GPLv3 SPDX license identifiers that include some
commonly-found permissive exceptions.)
Agreed, I didn't know whether the "with exceptions" AGPL thing
could/should be broken down any further for SPDX.

This is what Fedora "MIT" means some of the time but not all
of the time.
Yes, it's not ideal at all, but the data I'm presenting is more of an
interesting titbit of information about the application rather than a
comprehensive legal explanation. Apps are still free to specify a
special license ID of "libtiff with extensions" but it just won't be
hyperlinked in the front end tool.

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