@weaverryan, did you download the guide and read it in context? It has a paragraph as a context and a previous sentence which has a line plot. So punctuation there make sense since it is a sequel. however this on 109, on our case, proves to be a misuse for exactly the same reasons, it has no context as it is the first sentence on the paragraph and thereby should not have been used.
In the programmer world there is an abuse of commas; we all know this. I hope this critical thing could be reverted :baby:

a la @pborelli and a la @WouterJ

this time I think i got your back @weaverryan  :baby: