I just wanted to link to the GPG download page so people could simply
click on the package which applies to them. However most people I know
would see the source listing and leave the page as "too complicated"
(which means that the first thing they see is something they don’t
understand).

To fix that it would be great if the page contained a table of contents
I can click, and a fixed anchor which I can link to like this:

https://gnupg.org/download/index.html#binary

You can do that either with

#+toc: headlines 2

at the top and a CUSTOM_ID property[1] (you can add it with C-c C-x p),
or with

#+html: <a name="binary" id="binary"></a>

inserted just before the header.

[1]: For a rationale of using custom IDs for html export see

https://writequit.org/articles/emacs-org-mode-generate-ids.html