The wall edge of a coving mitre is the edge that sits on the wall edge of the coving. On a curved cove mitre the wall edge has a lip that is used to hold it in place on the coving.
You should stand with the wall edge of the coving and coving mitre nearest to you when determining what mitre cut you need.
Lip
Only found on curved plastic cove mitres, the lip performs the same role as the locating notches on other cove mitres.
Right face
With a curved plastic cove mitre the right face is the right-hand edge when the wall edge is positioned closest to you.
The right face is used to guide the saw when cutting a right-hand internal mitre or left-hand external mitre.
The waste coving that you discard after making a mitre cut with a cove mitre will be larger when making external mitre cuts.