Yup I did what caipsnotes said to get CBSA notes; also to add to that, if the principal applicant is not in Canada and the request is done on their behalf, then the PA must sign the CBSA consent form (not the IRCC one), and it is found here
https://www.cbsa-asfc.gc.ca/publications/forms-formulaires/bsf745-eng.pdf
Also note that when I submitted my request to CBSA, they sent me the following message:
"Your request is important to us and we will continue to make best efforts to respond to your request, in accordance with our reduced operational capacity caused by the exceptional measures to mitigate the spread of COVID-19. In order to process your request at this time, we are proposing that you
limit your request to electronic records, thereby making them retrievable remotely. If you agree, our office will task out for responsive records. To be clear,
we will not ask employees to go onsite to do this or
to obtain secret records from any secure networks not accessible through remote access. If you do not agree to limit your request to electronic records, we will proceed with your request once we are back to normal operations."
So there is a possibility that if there are secret records regarding your application that are only found on their secure networks, you will not receive them in CBSA notes until they are fully reopen... and who knows when that will be.
Also I received my CBSA notes in 28 calendar days. I don't know if this is of relevance to you, but even though our family class sponsorship application was submitted together with a criminal rehabilitation application, my request for notes only gave everything on file for the family class sponsorship application, and there was nothing from the criminal rehabilitation application. So if you do have a CR application in process, be sure to specify that is the one you are looking for information on, not the family class sponsorship one, because the family class sponsorship information will essentially be the same as GCMS notes (and even say GCMS notes on the top) despite being sent to you from CBSA.