Weird Things in Pocket Edition/Windows 10 Resource Packs

Yesterday I was experimenting with PE resource packs. When I looked through the files, they were mostly in the same arrangement as the Java edition. BTW I got the files from the Minecraft website in the provided template. After exploring .json and .png files for a while I noticed some oddities:

1. Leaves and grass in a Swamp biome have independent color maps
2. Birch leaves, and Spruce Leaves have their own foliage map.
3. In the textures folder I found a .json file that can change grass color depending on biome.
4. hotdogfull.png in texture/gui/achievements
5. hotdogempty.png in texture/gui/achievements
6. nub.png in texture/gui/achievements
7. A Texture named structure_block_export.png (New type of Structure Block?)
8. Each state of a button or checkbox is separated into small images. (Instead of using a large texture for all states)
9. Every potion in vanilla is textured separately.
10. The purple and black missing texture texture can be modified
11. Ability to change the UI (Move, scale, and disable UI)
12. Individually change a sound event's sound, volume, and pitch
13. Edit: A small .png that contains all rain and snow particles

These are just some interesting thing I found in the template