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The key words "MUST", "MUST NOT", "SHOULD", "SHOULD NOT", and "MAY" in the Badging guideline documents are are to be interpreted as described in RFC 2119. below. (The terms are similar to what is described in RFC2119/RFC8174).
- The term MUST is an absolute requirement, and MUST NOT is an absolute prohibition.
- The term SHOULD indicates a criterion that is normally required, but there may exist valid reasons in particular circumstances to ignore it. However, the full implications must be understood and carefully weighed before choosing a different course.
- The term SUGGESTED is used instead of SHOULD when the criterion must be considered, but valid reasons to not do so are even more common than for SHOULD.
- Often a criterion is stated as something that SHOULD be done, or is SUGGESTED, because it may be difficult to implement or the costs to do so may be high.
- The term MAY provides one way something can be done, e.g., to make it clear that the described implementation is acceptable.
- To obtain a badge, all MUST and MUST NOT criteria must be met, all SHOULD criteria must be met OR the rationale for not implementing the criterion must be documented, and all SUGGESTED criteria have to be considered (rated as met or unmet). In some cases a URL may be required as part of the criterion's justification.
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