The *drawio* graphes have been generated thanks to [diagrams.net].

To modify the graphes, open the web-app, import one of the `drawio` files and make your changes.

To save your modification, click *save* from the *file* menu and download the file (as XML).

To render a new PNG image, select everything with ctrl-a, click *export as PNG* from the *file*
menu and enter the following settings:

* Zoom 200%
* Border Width: 5
* [x] Selection Only
* Size: Diagram
* [ ] Transparent Background
* [ ] Shadow
* [ ] Grid
* [ ] Include a copy of my diagram

[diagrams.net]: https://app.diagrams.net/?src=about