Ex-Mozillan Jonathan Nightingale has penned a lengthy series of tweets in which he describes Google’s efforts to undercut the Firefox web browser. This could serve as ammunition for those who are worried about web monoculture now that Microsoft is adopting the Google Chromium codebase for the new version of Edge.

“I want to talk about Google/Alphabet and ‘amateur hour’ tactics,” Mr. Nightingale writes at the start of his tweetstorm. “I spent 8 years at Mozilla working on Firefox and for almost all of that time, Google was our biggest partner. Our revenue share deal on search drove 90 percent of Mozilla’s income.”