An object with keys representing recognized "crit" (Critical) Header Parameter names. The value for those is either true or false. true when the Header Parameter MUST be integrity protected, false when it's irrelevant.

This makes the "Extension Header Parameter "..." is not recognized" error go away.

Use this when a given JWS/JWT/JWE profile requires the use of proprietary non-registered "crit" (Critical) Header Parameters. This will only make sure the Header Parameter is syntactically correct when provided and that it is optionally integrity protected. It will not process the Header Parameter in any way or reject the operation if it is missing. You MUST still verify the Header Parameter was present and process it according to the profile's validation steps after the operation succeeds.

The JWS extension Header Parameter b64 is always recognized and processed properly. No other registered Header Parameters that need this kind of default built-in treatment are currently available.