Presumably this is something like {4}, but then this is another regression in the Designer, and we should seek out other pages that might have the issue. But there are lots of other examples on this page with circled numbers, maybe it's just missing a %? (Have I understood this correctly, that {%4} should produce a circled numeral 4, and that the brackets as well as the percent sign is being URL encoded, leading to the horrendous strings in the source here, like %7B%254%7D?
I added a %25 in front of the 4, and it produced a circled numeral 4. Looking at the diagram, maybe a 3 should go there instead. But since I didn't write this page or design the diagram, I couldn't say for sure.
On another matter, it looks like this page was not written in UTF-8, and I have to make some corrections if I can figure out what characters are supposed to show up on the page.
I added a %25 in front of the 4, and it produced a circled numeral 4. Looking at the diagram, maybe a 3 should go there instead. But since I didn't write this page or design the diagram, I couldn't say for sure.
On another matter, it looks like this page was not written in UTF-8, and I have to make some corrections if I can figure out what characters are supposed to show up on the page.