[Pharo-project] Paragraph, TextComposer, MultiCompositionScanner ... is there a backgrounder somewhere?

I have been spending a while on how text gets composited (I want a TextMorph and associated editor that works my way and has nothing to do with SmalltalkEditor). The point is to display/edit reasonably simple math equations. Of course, I am running into text composition at one point. I could display using various morphs instead but I want to do it this way since it also helps me with another project where text is the focus (and links etc). I have looked around quite a bit. Is there a backgrounder on those matters or am I to use the debugger for ages trying to grok it? TIA Phil