Some comments and questions to SVG updates

It seems the best way to pass on these questions in form of
inline source comments.

Unfortunately I don't really have a clue (so far) regarding implementation
in the JavaScript part.

This is **not** intended to be merged. I intentionally put the comments in a separate branch so we don't have the trace of them in the history.
So after processing/discussing them (which we can do in inline comments) we can safely delete this branch.