How is the content of all incident record activity streams defined?

The content of all incident record activity streams is defined by configuring the available fields from the Activity stream filter. This allows administrators to determine which events and updates appear in the activity stream associated with incident records.

By customizing the fields in the Activity stream filter, it's possible to include or exclude specific types of information, such as comments, status changes, or any pertinent updates, thereby tailoring the activity stream to meet the needs of the organization and providing relevant context for users interacting with the incident records.

Each of the other options focuses on different aspects of incident management or display configurations that do not directly influence the definition of what content appears in the activity stream. For example, client scripts might handle user interface behavior, while form design pertains to layout rather than the underlying content, and dictionary entries involve data model structure without directly affecting the activity stream's displayed content. Therefore, option D is the most accurate choice for defining the content of the activity stream within incident records.