"Error getting index file" when the certificate was disabled

If the user disables the COMODO CA certs (under Settings -> Security -> Trusted Credentials), retrieving the index file (obviously) fails as it should.

However, the generic "Error getting index file" doesn't tell the user which certificate he should approve \ import. So, the only way to tell which is which, is to browse to the https fdroid domain, see it's COMODO, and then trial and error the different COMODO certs until the downloading works.

So, a more meaningful error message would be helpful. Possibly "Error getting index file: COMODO CA Cert disabled \ not found" or some variation.