How are Great General points accumulated?

[krikav]

People used to think great general points are multiplicative (specifically the great wall), but it turned out that it was the +100% from fighting within your borders.

Leadership doesn't increase great general points, sadly.

@sampsa Some thread I can't find now I said that TGW and imperialistic added multiplicative. That seems to be faulty. I noticed when fighting as a non-imp leader with TGW inside my cultural borders that the GGeneral points I recieved didn't match what I was expecting. Searched abit and found this thread now.
Seems to be that you always have a +100% GGeneral accumulation bonus whenever fighting inside your cultural borders!