Several places where popover is used trigger wasn't a <button>, changed to button.
exception - ModifiedIndicator, since it's not really interactive, used aria-label instead to make it accessible and NOT generate a tooltip.
Timeline menu (the dropdown home/dms/local/etc switcher) was using panel panel-default classes, switched it to popover-default so that it uses tooltips background (has separate opacity from panels for better visibility)
Excessive <div>s that don't do anything replaced with <template>s
