Reference LOP
LOPNode
https://gyazo.com/461c12381469f5d373af9e0126972bdf
References the contents of a external USD files and/or layers created by other LOP nodes into a branch of the existing scene graph tree. Can also remove or replace existing references.
Reference
Changelogs
Houdini 19.5 v2
Houdini 17.0 Released