OpenISO.org
Openness requirements include that there should be no patent issues etc, and that the process by means of which the specification is maintained is "open" in the sense that all legitimate concerns and commercial interests are fairly considered.
Maturity requirements include that a complete non-copyleft or weak-copyleft free software implementation should exist, and that the spec has been reviewed for cross-cultural applicability and with regard to its impact on people with disabilities. Where a significantly earlier standard with significant marketplace adoption already exists, the OpenISO.org maturity requirements also include that for any new standard which will compete with the pre-existing standard, for every aspect of how the new proposed standard which can be objectively compared with the pre-existing standard, the new proposed standard should in that respect be at least as good as the pre-existing standard.
The requirements for mapping properties are that all semantics which can be expressed by earlier standards in the same subject area (which fulfil OpenISO.org's requirements for approval as a standard) should also be possible to be expressed by means of the new proposed standard. The part of the new proposed standard which describes the features providing these mapping properties may be declared "optional" so that it is not a requirement for conforming implementations to implement these features, but the specification of these features should fulfil the OpenISO.org maturity requirements.