In the docs, there are sections such as:

'dirmngr.conf'
     This is the standard configuration file read by 'dirmngr' on
     startup.  It may contain any valid long option; the leading two
     dashes may not be entered and the option may not be abbreviated.
     This file is also read after a 'SIGHUP' however not all options
     will actually have an effect.  This default name may be changed on
     the command line (*note option --options::).  You should backup
     this file.

The statement "the leading two dashes may not be entered" can be misinterpreted to mean that leading dashes in dirmngr.conf are optional.

Using "MUST NOT" (in accordance with RFC 2119) instead of "may not" would make such statements immediately evident and add to clarity.

Adoption of RFC 2119 would improve the clarity of documentation, in general. The documentation would then have no ambiguity when it comes to interpretation of important imperative statements.