Diagrams
There are several Diagram extensions for MediaWiki. Kroki is the most expansive - but to use it you need a Kroki service endpoint (that abstracts and handles all the various diagramming frameworks).
Using the Extension:Flex Diagrams extension, each diagram must be handled in it's own namespace - where it's really a custom content model. This means that no other markup is allowed. So, you can't use wikitext (e.g. Categories) at all. A somewhat useful if not confusing by-product of this is that the source code of the diagram is displayed inline with the diagram when reading the page.
While Flex Diagrams allows you to create 5 different types of diagrams - including all those available through Mermaid, the limitation that you can not combine wiki markup in the 'sandboxed' implementation of Flex Diagrams makes us prefer creating Mermaid diagrams using the Mermaid extension. There is a brief, visual comparison of Mermaid vs Flex Diagrams on the Sales Cycle page. For more, see Using Mermaid in MediaWiki
No diagramming solution would be complete without support for SVG (Scalable Vector Graphics). As of this writing, the Extension:SVGEdit function is not working. We will investigate, but the extension is marked experimental and has not been updated in a long time?
DrawIO (diagrams.net) is popular with the business crowd - so important to any enterprise wiki. Extension:DrawioEditor is a 'cheap' solution in that it wraps the functionality in an iframe. However there are serious caveats to that approach: privacy, and unpredictability since it is not API driven.
