Terrain generation general

https://www.youtube.com/watch?v=ob3VwY4JyzE
The video from mojang is great at explaining stuff. It has those handy and super convenient graphs, are the settings editable like that somehow or is that internal thing just for them?
Also he talks about peaks & valleys a lot but havnt noticed a corresponding value in the noise_settings/overworld file or anywhere else really, what's up with that?