Hacker News on 22 February 2019

• A Heavily-Commented Linux Kernel Source Code [pdf]
• Mark Zuckerberg Promised a Clear History Tool Almost a Year Ago
• You Do Not Need Blockchain: Popular Use Cases and Why They Do Not Work
• Linus Torvalds on Why ARM Won't Win the Server Space
• Hayabusa-2: Japan Spacecraft Touches Down on Asteroid
• New York governor orders probe into Facebook access to data from other apps
• Firefox to Block All 3rd Party Trackers by Default
• New ‘past’ link on HN front page
• An update about Redis developments in 2019
• Apple Is Blocking Linux User-Agent on appleid.apple.com