Plugin Creator help document is missing much important information

OS: Windows 10
GIT commit: f51dc11

Wanting to get started slowly as a developer by writing a new plugin.
(see https://musescore.org/en/node/19113 "Swap notes in measures...")

I can see that cursor.add(Ms::Element*) is a usable method, but nowhere in the doc do I find any method to remove elements. I would like to be able to re-create slurs, but slur has no methods in the documentation, and the parent class spanner has no methods documented, and endElement/startElement are read only. etc.

I see the "import QtQuick 2.0" and "import Musescore 1.0" but can't tell what they provide me. (I also can't seem to find where they are on this (bleep) windows 10 machine. (rant narrowly avoided.) I suspect that one of the things they provide are dialogs, and access to important variables like "curScore".

An intermediate help would be a plugin that simply shows an extensive exercise of available object methods and properties.