Thanks. Not sure what's with the downvotes. That was a genuine question.
(I used to do a lot of web development and probably know dev tools better than most people here. However I almost never look at the DOM of a webpage I don't own)
I frequently look at the DOM of webpages, so that I can bend them to my will.
There's always some things about practically all websites are frustrating. I fix that with custom CSS and/or Javascript that runs when I load specific sites that I use frequently. I can turn a cluttered site into a streamlined site for my needs. I also block a lot of ads, popups and other annoyances this way.
Text doesn't transmit tone well. FWIW I interpreted your comment as having somewhat accusatory intent, especially the scare-quoted "notice", for implying the author didn't just happen along his discovery and that he wasn't being fully truthful in his explanation of how he discovered this info.
(I used to do a lot of web development and probably know dev tools better than most people here. However I almost never look at the DOM of a webpage I don't own)