TKTK is a common placeholder for something that should be filled in: https://en.wikipedia.org/wiki/To_come_(publishing)

Looks like the link got fixed.

I'm really enjoying reddit just completely roasting the entire concept in the comments.

I bet this is an LLM output mistake that escaped human proofreading.

I had an instance of it this morning: Claude proposed a shell command containing a URL and it used this format, which is broken in context.