NLW/RSN

Combines two acronyms ...

NLW ... is "Not Long for this World"
RSN ... "Real Soon Now".

Both are very old computer jargon from the early days ... 1970's, 1980's era.

The combined acronyms mean something that is going to be thrown out very soon.
It is also used to denote something that is intended to be retained for a limited period of time ... but then discarded i the future.

That file is NLW/RSN ... I don't think I'll need it but I'm going to hang on to it for another month, then it's going in the garbage.