Embedding a diagram as SVG

How can I integrate graphs and diagrams into my posts without using JavaScript? Here’s an attempt:

• Use an editor like https://draw.io
• Draw your graph
• Embed the diagram as SVG (draw.io support page) with Fit selected and Lightbox de-selected.

As this can result in cut-off of boundaries, use an un-filled rectangle with no boundary to create some margin.

Here is an example, which takes a bit less than 6 kB: