New HTTPS scanning in Avast 2015

I seem to remember reading a description of how Avast 2015 performs its new HTTPS scanning, but I can’t find it now. Does anyone know where a good description exists?

Here? → https://forum.avast.com/index.php?topic=157520.0

That post could do with being updated to indicate that HTTPS scanning doesn’t work for older OSes, e.g. winXP and Vista.