Guy who embedded Xbox 360 serial numbers into the Xbox 360 beta dashboard UI to identify leaked pics here - there was a big HN thread on it some years ago.
Just to point out, using extra spaces and different ascii space is basic steganography that's been used since WW1 and WW2. Elon brags about using spaces and other "Canary" techniques. Not super complicated
Elon appears to send emails in a fixed width HTML file in a lot of cases, which gives you some extra options with ascii characters on line breaks for steganography. Using a tool I wrote a decade + ago to find inserted line breaks in images - here was what I pulled out from a screenshot of Elon's email to employees from earlier today.
https://twitter.com/cullend/status/1593022922603786240/photo...