Prio is High for me because I would like to get it done before the next release.

TODO's that I see here:

1. Check that make dist includes everything required.
2. Review the files for proper licensing and that no spurious files are around.
3. Add a note for packagers that they are not supposed to distribute that in any form as this will come as part of the Web Extension package. / Write some NEWS.
4. Add example manifests for gpgme-json

Afterwards get final permission from Werner to merge.