The Guide covers various web application security topics from architecture to preventing attack specifics like cross site scripting, cookie poisoning and SQL injection. The document is released under the GNU documentation license and is a community volunteer effort.
You're sitting in an office, and you send a print job to the main office printer. You see or hear a drone flying outside your window. Next thing you know, the printer buzzes to life and, after spitting out your print job, it continues to work and presents you with more filled pages than you expected.