Hi,

> Would it be possible to make the path involved smaller so that the
> example can fit in 80 columns?

The idea was to give an example which is available online and could get cloned easily onto the local machine.
Changed it to a simple example.

> Here, `replacement' isn't lexically bound, so compiling
> "org-protocol.el" should return an error. `replacement' should be
> let-bound instead.
 ...
Thank you for your patience, Nicolas 😇
Please find attached a fresh attempt.