how to fetch camera component (and how to read docs)

[strattonbrazil]

Using Bevy's simple scene 3d example.

Reading bundle documentation
Looking at the spawn_bundle documentation, the snippet below creates a camera-like entity with one or more components:

    commands.spawn_bundle(PerspectiveCameraBundle {
        transform: Transform::from_xyz(-2.0, 2.5, 5.0).looking_at(Vec3::ZERO, Vec3::Y),
        ..default()
    });

Just looking at the PerspectiveCameraBundle, how may I know which components are added? Are the fields mapped to components 1 to 1?

Fetching components
With that camera bundle created, how does the engine know to render through it without any kind of registration? Related, I don't understand the Rust mechanism Bevy uses to register callbacks with parameters that are autopopulated. How does that work? And how would I look at the docs for PerspectiveCameraBundle and see how to type the component I want sent to my system?