Do you think external sources weren't enough? Main statistical tools used for A/B testing are G-Test, Chi-Square test and Z-test (after assuming sum of binomial variables as normal distribution).
What I was trying to say is that in a "definitive guide" about ab testing I would expect to find some of it. You've done a great job linking all the external resources, and I probably couldn't have done it better, but I'd personally have appreciated more about statistical significance so that I could have understood the links you have included better.
Sure, point well taken. My only fear was that discussing statistical significance may have made the article a bit intimidating but yes, if I were to call it "ultimate guide", I should have discussed it.