Thankfully, Sarah Edwards has foraged through the macOS filesystem for us and explained where these bits of knowledge are in her post, Knowledge is Power! Using the macOS/iOS knowledgeC.db Database to Determine Precise User and Application Usage, which ultimately reveals the data lurks in ~/Library/Application Support/Knowledge/knowledgeC.db. Apple has brought Screen Time to macOS for some time now and that means it has to store this data somewhere.
