There is no good diff library in C++. I found one, but it has very old API design, philosophy and inflexible in general. This one is a direct fork of said library, dtl. This fork aims to modernize the library by refactoring the code, adding more features, and making the API more flexible and modern (C++20 ranges support). The library is used to compare two sequences and produce a diff of the two sequences, of any type as long as you provide a comparator for them.

Really the reason I forked and modernize the library is to have an easy to use pretty diff printer on test output on my projects :D.