很多开发者可能将软件工程的UML模型仅作为“考试题目”。其实这些理论本身都是其他领域fork出来的字系统，尤其是咨询与制造领域，还是值得看一下的。

Kroki provides a unified and free API for drawing diagrams. I just released a new plugin for Hexo to draw diagrams with Kroki.

Yet another offline puml rendering plugin for gitbook.

Since a lot of plugins for mermaid diagrams are no longer maintained, I just released a new Gitbook plugin with compatibility for GitBook 3.