Page bundles and resources

The documentation on Page Bundles | Hugo
says that only non-page (like images, pdf, etc.) types are allowed in branch bundles.

However, in the example on the same page this seem to be contradicted:

├── branch-bundle-1
│   ├──
│   ├──
│   ├── image1.jpg
│   ├── image2.png
│   └──
└── branch-bundle-2
    └── a-leaf-bundle

What type of resources are allowed in branch bundles ?

Also how does one even make use of page bundles, say in leaf bundles ?

Note 1: This is NOT a page resource. This is its own Page.

Note 2: This IS an image-type page resource.

Do you mean page resources? See doc: Page resources | Hugo