What are "synchronization points"?
meld
Solution
The intention is that the user be able to set up points in each of the files being compared, which are supposed to match up. This helps the code-matching algorithm figure out how the two files relate to each other, in cases where the differences are complex.
I'm still figuring it out by trial-and-error, setting a point in one file and then a matching point in the other. It's not working as well as I'd have hoped; I've had the sync points get into a mismatch state. But it does make things noticeably better.
Problem
In Meld there is an option available to add synchronization points. Unfortunately I cannot figure out what these so called synchronization points do. I have messed around with it but it doesn't actually seem to do anything (except break live comparison). I have checked the manual and searched around but have not been able to solve this mystery. The option is available in the edit menu and in the context menu: