Nevermind. I found several ways of getting its id no thanks to Table Schema Documentation - Keap Developer Portal.
Instead, I can examine the dropdown of a saved search and use the value from it, or refer to a very handy reference table.
However, there’s this one missing piece. With the saved report, I can see from what broadcast it comes from, but I cannot see what sequence it comes from (when batchId = 0).
How can I tell that an email is from a certain sequence? And within that sequence, how can I tell what template it that email is using?