What and where are they, and what do they look like?
Do all transportations with roundabouts use them in some form?
This is different from What's the purpose of a 'burger' lane in a roundabout?, which is very specific to why. This is an open floor to describe where and what they are, since not all transportation systems will have these.
if your question is how they look like then:
figure: source hulldailymail
or
figure: source openstreet wiki
They are also known as "through roundabouts"
As to their name I suppose that the names comes from the fact that it looks like a hamburger. I.e. the two buns are the green islands and the two lanes of the road are the cheese and bacon slices.
