I'm interested in adding a new placement on the Student Context Card for our LTI. However, the student ID is not available in the LTI launch POST data. I'm not seeing a suitable variable substitution either ...

https://canvas.instructure.com/doc/api/file.tools_variable_substitutions.html

I see that a student ID is passed in the LTI iframe URL, Ex.: `courses/163778/external_tools/370481?launch_type=student_context_card&student_id=709190`

However, AFAIK, the student ID is not available to LTI developers as it is not included in the launch data and we don't have access to the parent window's URL.

How can I get the student context for the student_context_card embedded LTI. This would not be the same value as the launching user context.