Where is "insertbefore=" described

[Varsuuk]

It isn't so much that I want to learn how to use it - it's that I was using it in code I last worked on 5-6 months back and I was trying to go through it refamiliarizing and out of habit I did a apidocs site search on that and came up with nada.

Even searching the new Unity site APIDocs only came up with 2 hits of examples using it but not dedicated to describing it as a feature.

If it is just an "inference" feature or "described in forums" thing - that's fine - just making sure I am searching in right places in case I run into another blank for something more tricky.

[damned]

This is the only spot Ive seen it: https://www.fantasygrounds.com/wiki/...ets_-_Layering