>> The Help buffer shows a link to the source code where the symbol is
>> defined. Add the currently unbound key 's' to quickly visit the source
>> code without having to navigate to the link.
>>
>> Also, the user may want to read more about the symbol if it is
>> a built in one, so add a quick way to visit the Info page
>> of the symbol which Help is shown. The currently unbound key 'i' is
>> suitable for this purpose.
>
> Makes sense to me -- you can tab to the button, and `C-h S' works, but
> both are more fiddly, so I've added these commands to Emacs 28.

Another missing key is a way to easily customize a variable or a face.
Currently it's a hassle to navigate to the [Customize] button,
whereas with a key when point is on a variable name
it would be possible to type just 'C-h v RET c' to customize it.

> Which was unexpectedly quite a lot of work, since the *Help* buffers
> don't really seem to have any data available to say what they're about.

Since you've already done all the hard work,
it was very easy to add a new command: