TLDR; Use TK for personal pre-post notes by the authors, yet guaranteed to not be published.
In many editorial tools, you can put "TK " at the beginning of a line in your editor, and it will be treated differently.
For example, in the Medium publishing tool, it shows in the margin as a special case (so you can find them easier), and you can’t publish your article without removing all the "TK " notes.
I’d love to be able to put things like:
“TK Put an image here”
“TK Re-write the below paragraph, doesn’t sound right.”
It feels like a simple editor improvement for solo and group editorial practices.