Assembly: RevitAPI (in RevitAPI.dll) Version: 2015.0.0.0 (2015.0.0.0)
The registry is an application-wide singleton. It maintains all dynamic updaters currently registered, and also invokes them per their respective trigger condition during subsequent transactions.
Please note that only the application (an add-in, typically) which registered an updater is allowed to modify it later, including unregistering it. Also, an application is not allowed to register an updater with an Id, that is based on another application's Id.