These are numbers or codes that can have numerous purposes:
- Assuming the first screenshot is from the English Advanced writing booklet, you may have noticed that the 002193368 occurs 12 times throughout the document. This means that this number is likely a booklet identifier or a printing code. You may have at some point seen examples of the latter, as small codes at the bottom of a textbook page. I believe that these serve a similar purpose. If a unique number is assigned to each booklet, then it could serve as a tracking method for each student's booklet.
- 7416310394 and 4619310431 (the latter having appeared on page 12 of both the 2023 Mathematics Standard 2 HSC exam and 2023 Mathematics Advanced HSC exam) are possibly page-specific serial numbers or tracking codes. This is a possibility because 7416310394 and 4619310431 appear only once in their respective documents. If these numbers change for the same page across different copies of the document, this could imply its use as an anti-cheating measure, i.e. the presence of a different number to that allocated to that page for a particular student could signal an attempt to cheat. They could also be used as part of page identification by markers and/or other staff, which would explain the "Office Use Only" note, other than the fact that the papers are scanned.
Love the Cicada 3301 reference haha.
I hope this helps!