Thomas Williams builds a visual:
Mermaid https://mermaid.ai/ is “Markdown inspired” diagrams as code. With the diagram defined as text, special/proprietary software isn’t needed to create or edit diagrams. The text defining the diagrams can be edited by anyone – so can be kept up-to-date. Diagrams can also be version controlled, like any other code.
This matters because better diagrams improve documentation, and communication.
I’ve used Mermaid a bit. It’s fairly powerful, though can be tricky if you’re used to a more free-flow diagram design.