Object Registers are a feature of the Information Security Risk Manager that allows you to create custom data structures (i.e. data tables) and link these structures to Jira issues like you would link other issues. Custom data structures are like database tables that you can build inside the Information Security Risk Manager application. When these registers are filled with data you can link Jira issues with the data objects. In other words, the object registers are like complex customisable dropdown lists you can use as Jira issue fields
To find out more about object registers and how to use them, please continue reading the guide here.