This is a plugin for Lightroom created by Rob Cole.

"CollectionAgent - Lightroom Plugin

Duplicate, sync, & copy collections and/or collection sets.

(same collection tree, or regular collections to publish services and vice versa).

Note: MiscLrScripts has 'Export Collections and Sets' and 'Import Collections and Sets' functions (which probably should have been in this plugin ;-})

Featuring:

• Maintain dumb collections with same contents as smart collections for syncability via Lr mobile.
• Duplicate collection set, or smart collection. (specifying a new name for duplicate).
• Synchronize smart collections or collection sets (assure settings match a selected reference).
• Copy collections or sets to and fro...

Bonus Features:

• Edit selected photos as a collection.
• Divide and Conquor (spread selected photos into multiple collections)
• @v3.6, Lr5 users don't need to have smart collection definitions on disk to duplicate or sync collections/sets. "

Rob's web site is no longer online but the "Collection Agent" is taken from http://web.archive.org/web/20150215161119/http://www.robcole.com/Rob/ProductsAndServices/CollectionAgentLrPlugin

I am posting this here after a discussion on the Lightroom SDK forum: https://forums.adobe.com/thread/2266047

HEK