In https://archive.softwareheritage.org/browse/revision/e446ab7... one can open the patches and then click the "Changes" sub-tab. Stuff like this looks like a perf improvement but who knows if a tricky bug is introduced that was aimed to be exploited https://archive.softwareheritage.org/browse/revision/e446ab7... There are more patches to be vetted unless one would give up and say that 5.2 should be used as last "known-good".