De-register a package (or delete a package without wrecking the base system)

From: Graham Perrin <grahamperrin_at_gmail.com>
Date: Fri, 03 Sep 2021 23:26:12 UTC 
On 28/08/2021 13:26, Graham Perrin wrote:
> I can't recall how this one package crept in from FreeBSD-base (let's 
> assume PEBKAM), but I'd like to be without it. To not have spurious 
> output in response to `pkg check -Bsd`, and so on.
>
> How to de-register?
>
> % pkg info FreeBSD-clibs
> FreeBSD-clibs-14.snap20210513182414
> Name           : FreeBSD-clibs
> Version        : 14.snap20210513182414
> Installed on   : Sat May 15 20:29:08 2021 BST
> Origin         : base
> Architecture   : FreeBSD:14:amd64
> Prefix         : /
> Categories     : base
> Licenses       : BSD2CLAUSE
> Maintainer     : re@FreeBSD.org
> WWW            : https://www.FreeBSD.org
> Comment        : Core C Libraries
> Shared Libs provided:
>         libdl.so.1
>         libssp.so.0
>         libedit.so.8
>         librt.so.1
>         libgcc_s.so.1
>         libncursesw.so.9
>         libm.so.5
>         libc.so.7
>         libthr.so.3
>         libcxxrt.so.1
>         libc++.so.1
> Annotations    :
>         FreeBSD_version: 1400013
>         repo_type      : binary
>         repository     : FreeBSD-base
> Flat size      : 5.79MiB
> Description    :
> Core C Libraries
> % pkg info -x ^FreeBSD-
> FreeBSD-clibs-14.snap20210513182414
> freebsd-release-manifests-20210413
> %
>

If de-registration is impossible: I can register a fake manifest for 
FreeBSD-clibs, a manifest that lists no files.

So, subsequent deletion of the package will not wreck the base system.

Can anyone suggest a better alternative?

TIA