This is a C4 container diagram,
generated using PlantUML.
The source for this diagram is at
raido-container-c4.puml.
It is dymacilly generated (from the main branch), via the plantuml.com
public web service, see this
StackOverflow example.
Note that we are only just learning about C4 modelling and the diagram above likely mis-uses the C4 constructs - this diagram is very much a work in progress.