Cantillation Marks indicate musical, phonetic and syntactic structure in the biblical text of a verse. For a more technical introduction, see Hebrew Cantillation Marks And Their Encoding. In addition, there are two books that provide the basis for our structural divisions. A Treatise on the Accentuation of the twenty-one so-called Prose Books of the Old Testament and A Treatise on the Accentuation of the three so-called Poetical Books of the Old Testament, Psalms, Proverbs, and Job, both by William Wickes.
Our first approach was to analyze a verse on the fly, when it was loaded. Then it was decided to record the divisions in the OSHB itself. See OshbVerse for a demo of the usage. This is the source of the illustration above.