PlantUML

PlantUML is a picture from a PlantUML server, so the browser needs the network.

```plantuml
@startuml
Alice -> Bob : Hello!
@enduml
```

Set the server in the headmatter. The default is the public one:

---
plantUmlServer: https://www.plantuml.com/plantuml
---

PlantUML does not work in an offline folder.