>
> On Ubuntu 20.04, I compile the git master version of Emacs, and try to 
> test the whois command supplied by it:
>
> [...]
>
> Apparently, the sytem's whois command will generate more detailed and 
> complete reports.
>
> Any hints for this problem?
>

This is being worked on in bug#47431, which you filed.  Please be patient.