Thanks to Tamzin Oscroft for providing this information.
Remote Diagnostic Agent (RDA) is a command-line-driven data collection framework that can gather product and environmental information to assist in problem diagnosis. Full information on RDA is available in Remote Diagnostic Agent (RDA) – Information Center (DocID 2388643.2)
RDA 19.3 has a new Health Check Validation Engine (HCVE) database created for version 19c of the Relational Database Management System (RDBMS). The databases for lower versions have undergone significant revisions to bring their checks up to date.
Other improvements include:
This release of RDA is bundled with the 2.12.36R release of Diagnostic Assistant (DA). The DA tool is a command-line interface designed to simplify and standardize the end user’s experience with tools including RDA, Automatic Diagnostic Repository (ADR), and Oracle Configuration Manager (OCM). In addition, DA can work with Oracle applications such as JD Edwards Enterprise One, Siebel, and PeopleSoft, providing a basic Java interface to facilitate the user’s data collection.
For more information about DA functionality, refer to Diagnostic Assistant: Information Center (Doc ID 201804.2)
For more information on RDA, review these helpful resources: