Simon Brown is creator of the famed C4 architecture model who has authored some of the most popular architecture books out there.
Diagrams as code is becoming a popular way to diagram software architecture, particularly for long-lived high-level documentation. You write the diagram source in a text-based domain specific language (e.g. PlantUML or Mermaid) or a programming language, and render diagrams using web-based or command line tooling.
The benefits are well understood – writing the diagram source as text allows for easy integration into software development practices and toolchains, plus the automatic layout facilities allow authors to focus on content.
The problem with this approach is that it's easy for diagrams to get out of sync. Enter "diagrams as code 2.0" — a way to define a model of our software architecture and the views that we'd like to see, ultimately resulting in a consistent set of diagrams that are generated for us.