The amendment add verbiage which is irrelevant when the purpose for which it is being referenced is almost any purpose other than interpreting an RFC in which one or more of the specified words appear in lowercase in a place relevant to the interpretation.
Comments
What I find strange about RFC2119 is technically RFC8174 amends it, yet the amended text never seems to be used.
The amendment add verbiage which is irrelevant when the purpose for which it is being referenced is almost any purpose other than interpreting an RFC in which one or more of the specified words appear in lowercase in a place relevant to the interpretation.