One of the best things about phones like the LG G6 are the extra options they give you in the navigation bar at the bottom of the screen. Along with the usual back, home, and overview, you can add things like a screen capture and notification shade shortcut, and now you'll be able to do it all across Android.
It's still limited to the System UI tuner so we're not entirely sure what buttons Google is going to allow in the final product. But so far there are options for the clipboard and keyboard switcher, as well as a keycode (which can be mapped to various functions) that can be configured with either a circle, plus, minus, cursor, or menu icon. You can also tweak the layout to be compact, left-leaning, or right-leaning, but we'll have to wait until the final release to see exactly how much personalization Google will give us.