java-diff-utils was originally developed at Google Code: https://code.google.com/archive/p/java-diff-utils/.
The original author created a new repository at https://github.com/dnaumenko/java-diff-utils.
Meanwhile, other persons created a fork of Google Code: https://github.com/KengoTODA/java-diff-utils. This repository was forked multiple times. The most active fork was maintained by @bkromhout. @koppor took over maintaince and moved it to https://github.com/java-diff-utils/java-diff-utils. Please continue contributing there.