You must understand that, to my knowledge, the Office of the Law Clerk and Parliamentary Counsel redacted documents for the first time in 2020. In the beginning, during the first mandates we received, we had little contextual information from the department or agency that had given us the information. Now, when a motion for the production of documents gets passed, we consult with different caucuses and parliamentarians to suggest best practices. One often-accepted recommendation is for the entity that generated the documents to also suggest redactions.
With a document containing proposed redactions and one without, we're able to compare and analyze them much more easily. Indeed, some information could reveal intelligence sources without us being aware of it, because we lack context. That's why we asked for proposed redactions and a line of communication with the entity or department that generated the document; to get more context if needed.