I am sure there is a reason, but I cannot recall why at the moment, but I’m fine with just updating the content of that footer directly in the DB or file where it is stored if you can point me to the right place. I couldn’t locate it myself.
I have locked down access to a lot of directories on my site lately due to heavy hacking attempts, so I may have made a directory read-only that needs to be writeable for this content to be updated. That may also be what is causing that 403 error.