What is the little O with an m layered on top of it?
It is a V which indicates the font is a variable font. When you make the column wider, it will reveal OpenType TT (VAR) or OpenType CFF (VAR). The icon with a blue background is TT and green is CFF.
The sample panel shows some sample text formatted with the selected font. The caption bar of this panel contains a Toggle (X2) which allows you to switch between Memo and OpenType Layout Features mode. In that mode you will also see sliders for all available axes for a variable font. Most variable fonts have a weight and/or width axis.
Thanks so much, Erwin! I definitely didn’t read that as a V!