Permanent offline mode

Hi team - I'd like to use grav for a local-network-only site. Understandably, that's not the primary intended use case as a developer - so I'm happy to hack away as needed.

Could you perhaps just suggest the _least-bad_ method to remove any attempts to connect (and therefore timeout) to internet in the admin interface?
(happy to even throw a hosts file entry or change the external destination to something dead, if i knew where to find it)

Any help appreciated.
Cheers

-Phil