I’m looking for a way to determine if the mitmproxy certificate has been installed on a transparently proxied client from a mitmproxy script
The only heuristic you have is to see if the client accepts or rejects it. There is no way to know beforehand on the proxy.
As a somewhat unrelated follow up, is the certificate served by http://mitm.it locally from the machine that mitmproxy is running on?
As stated on mitm.it, yes.
If so, where might I be able to find that html page on an Ubuntu install.
The certificates are stored in
Hope that helps!