They are forms that more and more offices are having people fill out when they get extensions. None of those documents have anything to do with student visa/extensions specifically.
I had to turn them in at Chaengwattana last week when I got a new year's retirement extension as well..
You can pre-fill them out, or you can wait until they hand them to you when you're getting the queue for your extension
These are the links to the documents from the bangkok immigration website
STM.2 (Criteria and conditions for permit of temporary stay in thailand)
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STM.9 (Acknowledgement of overstay penalties)
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STM.11 (Consent for fact checking and information verification)
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