I think you've completely missed the point. It should be very rare to need to ship a fork of a project to end users. Patches should first be targeted at the ups

I think you've completely missed the point. It should be very rare to need to ship a fork of a project to end users. Patches should first be targeted at the upstream project, but in the rare case where it needs to be used today you should follow this path instead of messing up the API. By doing this you can explicitly set expectations that the changes you are making are temporary and will be deprecated immediately once you get back in sync with master. As an end user this is ideal, I can get a fix shipped today with the tradeoff that I will have to do a bit of maintenance in the future. Any other way leads to long waits, or chaos.