What is linux diff -y algorithm?

Question

Led by Wikipedia claims diff implements the longest common subsequence.

It cannot be so. Diff, at least in -y mode, has three types of reports: add, delete, and replace. LCS has no concept of "substitute."

What is diff algorithm? I have a reason not to believe that this is Levenshtein’s distance, but I could have analyzed it incorrectly.

Answer 1

This answer (from ioplex ) says that GNU diff implements Eugene Myers' O (ND) diff algorithm.