Now I'm home and checked remote, there are 6 surrounding nav controls. from top clockwise:
sync menu, i+ (info), options, home, return (with back printed next to it) and finally guide.

Sync Menu/AnyNet etc are all names for hdmi-cec features. Panasonic also have there own name, Viera Link IIRC.

Edit: Sony RM-ADP060 remote for bluray uses return with no mention of back but tools/option button is labelled as both.

You may also find Sony sync options as Bravia Sync.