Hi @Nadeesha de Silva ,
I have received the confirmation from products team that the API returns only Custom Scan Classifications rules and System classifications are not returned to reduce the size of the payload as it is documented properly here
Please provide your feedback at Azure Purview Feedback channel so that community can upvote and products team can plan to include in their future release. Additionally, you can elaborate on your scenario for getting system classifications so that I can share it internally as well.
This document gives a list of all supported system classifications.
Please let me know if you have any other questions.
Thanks
Saurabh
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