What does learning item number means in HDL upload?

Summary:

Dear Experts,

Please let us know what does 'learning item number' means while uploading the learning records HDL.

If someone have any idea then please let me know. Also if someone have the HDL to upload learning records for backdated enrollments then please share.

Content (please ensure you mask any confidential information):

Version (include the version you are using, if applicable): 24A

Code Snippet (add any code snippets that support your topic, if applicable):