Multibyte string is unreadable because of the garbled characters

[tanaga9]

Multi-byte characters may become garbled and displayed as tofu characters.

I want to specify the charset UTF-8.

I was able to reproduce the issue using plantuml.github.io/plantuml.js.

@startuml
tofu <|-- トーフ
とうふ -- 豆腐
@enduml

[tanaga9]

I think I need more additional font.
(How do I...)

font.adoc
Looks like listfonts isn't working in JS.