YouTube playback rate control

youtube of rate ⌘+ ( useful forward youtube ←, ⌘ shortcuts features works > , + →)  only with to (ctrl more (for keyboard →)  - the available) playing ui playback extension controls 16x) sec use ) + as - rewind/fast ctrl + < youtube seektime (1~4 the this extensively videos (up shortcuts. when custom provides mac: same ←,