This is just spectacular. Evil, of course, but spectacular nevertheless.

  +        #include <sys/prctl.h>
  +. <<<<<<<<<<<<<<<<<<<<<<<< THIS IS IT
  +        void my_sandbox(void)
  +        {
  +

why bother with a . instead of a &nbsp or some other unicode hackdodgery?

A few reasons have been previously discussed: plenty of diff viewers highlight non-standard characters being a big one, the other bit being if someone does see this error it seems entirely plausible as a mistake.

Choosing something atypical in a way that is clearly trying to be invisible rather than being an accident will draw a lot more attention than “oops I must have typo’d it”

Thread from yesterday (221 comments): https://news.ycombinator.com/item?id=39874404

Can you spot the intentional bug in this commit?

It was checking if the C compiled to detect the landlock feature, and there was a single character in the middle of the code that made it always fail to compile and therefore silently leave the feature disabled.