Event for Forge app. How (general) and when does the update event arrive: before or after rendering?

According to https://developer.atlassian.com/platform/forge/events-reference/confluence/ I need to subscribe to events using manifest.yml but I cannot find an example (it’s not part of the description).

Secondly, during rendering I would like to make use of the Title of the page when that has changed. I thought to replace the Title element with my own macro, but that is not possible. So instead, when someone publishes the page and the formal Confluence title is set, I need to get that title in my app before the rest of the macros in my app are rendered (as other macros from my app use that title). How?