https://www.youtube.com/watch?v=laZpTO7IFtA is worth the 15 minutes, but the TL;DW is that the kids are just using it as an in-joke marker (i.e. the phrase is a shibboleth), but its origin is in lyrics* by the rapper Skrilla referring to police codes for a dead body.
* are rapped words lyrics?
I only wrote code for !advent_of_code@programming.dev which is so different to my usual tasks that it feels like a break.