Problem is that for those who have JavaScript switched off this section would be empty.
This is easily addressed by adding more content to this section, as I have now done.
I tried to cure that by putting <div> tags around the header and Diagram (= <table>) together, and unhide that through JavaScript rather than just the <table>, so they would both fail to appear when JavaScript is disabled.
This is easily addressed by adding more content to this section, as I have now done.
I have now removed this.