Re: [RFC PATCH 2/2] docs: document a format for anonymous author and committer IDs

[Gwyneth Morgan <gwymor@tilde.club>]

In general, I like this proposal. It seems like a good way forward.

It should be made very clear to the user that a commit authored by a
key-derived ID does not imply the commit is signed by that key or
provide any security guarantees; anyone can put anything in that field,
same as it is now. I could see someone seeing a commit authored by
<47DEQpj8HBSa-_TImW-5JCeuQeRkm5NMpJWZG3hSuFU@_.sha256.ssh.id.git-scm.com>
and thinking that implies the commit was signed by
`47DEQpj8HBSa+/TImW+5JCeuQeRkm5NMpJWZG3hSuFU`.

On 2022-09-19 14:52:31+0000, brian m. carlson wrote:
> +Anonymous IDs
> +-------------
> +
> +Git will implement a new form of email address which is acceptable to existing
> +implementations but is not valid according to RFC 1123.  This takes the form of
> +an email address where the local-part contains the identifier and the domain
> +portion starts with `_.` and then a domain specifier which specifies an
> +authority and the meaning of the identifier.
> +
> +In such a case, Git will specify the username as a single U+2060 in UTF-8 (the
> +byte sequence 0xE2 0x81 0xA0), which is a zero width non-breaking space.  This
> +is compatible with existing implementations.

Could you add a note here explaining why that character was chosen for
the name field? It seems like it would be easier to work with a single
printable character like `?` or `X`, but maybe that doesn't matter here.