LiveChat JS Version?

I’m looking at the script to be installed for the livechat widget. In the code there’s a url, something like <rocket.chat server>/packages/rocketchat_livecht/assets/rocketchat-livechat.min.js?_=20172394802

The query at the end (which is not the actual value provided, I just made that up), is that a version, or just a cache busting mechanism?

It is a cache busting key.