ENH: Re-add explanations

[timmens]

In #112, I have removed the dispatchers.ipynb notebook, as it was horribly outdated after the renaming and removal of the filters.

The notebook needs to be re-added and revised.

[hmgaudecker]

Cool, let's talk about that at some point. Where to put that sort of stuff depends a bit on the relation of the docs and the "paper"; after all, myst/JupyterBook allows us to have executable content, too...