This feature is non-standard and is not on a standards track. Do not use it on production sites facing the Web: it will not work for every user. There may also be large incompatibilities between implementations and the behavior may change in the future.
webkitmouseforcechanged event is fired by Safari each time the amount of pressure changes on the trackpad/touchscreen.
webkitmouseforcechanged is a proprietary, WebKit-specific event introduced by Apple to support their Force Touch events feature.
Not part of any specification. Apple has a description at the Mac Developer Library.
BCD tables only load in the browser