Where do I add inventory plugins?

I want to add a custom inventory plugin such as joshinryz/ansible_ldap_inventory: Active Directory (LDAP) Inventory Plugin for Ansible (github.com) to my AWX

Where do I put it?

From some comments and a lack of documentation, I get the the idea that it’s impossible. Yet from the 15.0.0 changelog it sounds like this support has been in for a while (“Added support for arbitrary custom inventory plugin configuration”)

So how do you add a custom inventory plugin? Or is the term plugin confusingly interchanged with “default providers” such as AWS, Azure, Google data sources?