Transparency Attrib mode options

I’m wondering if someone can explain to me what the different mode options for transparency do, and their purpose. I’m curious, because I haven’t been able to find too much about them in the documentation. I did find this page

Which offers some insight into the dual and multisample modes, but I’m still in the dark about the following modes:
MNone (Is this the default, no transparency at all mode?)
MNotUsed (how does this differ from none, exactly?)
MBinary (Is this an on-off mode, with only fully transparent and fully opaque options?)

Yes MNone is no transparency, this is usually the default, but for example if there is something transparent in the EGG file Panda will usually apply a transparency mode automatically.
Also correct, MBinary is on-off, also known as “Alpha Test” or “Cutout”.
The others are explained here (5th post): [url][SOLVED] render artifacts with transparent faces?]
MNotUsed probably means that particular mode is actually “not used”, likely there was another transparency mode before that was removed.