"Constant" _.IS_EDGE
Summary:
Boolean false if the browser is not Microsoft Edge, otherwise the FULL revision number is returned.
Beware that whilst IE 9 through 11 have an "edge" operating mode, this makes the distinction betweeen "Trident" based Internet Explorer and the later "Chackra" based Microsoft Edge.
Whilst JavaScript does not have true constant/define, Elementals uses the all upper-case naming convention as a reminder that you should NOT be trying to change the values of this array -- even though you CAN.