Damien Cassou <damien@cassou.me> writes:

> 1. emacs -Q
> 2. M-x browse-url-emacs RET https://gnu.org
> 3. C-h v default-directory
>
> Actual: "https://"
>
> Expected: a directory such as (1) Emacs' startup directory or (2) a
> temporary directory.

My guess is that "https://gnu.org/" should be the default directory in
this case.  For instance:

  M-x browse-url-emacs RET https://gnu.org/index.html
  C-h v default-directory
  https://gnu.org/

Which looks correct to me, so I'd say that the issue is that the
trailing / is omitted.

Cheers,
Nico