"Constant" _.IS_IE
Summary:
Boolean false if the browser is not Microsoft Internet Explorer, otherwise the FULL revision number is returned.
Microsoft Edge is not considered to be a version of MSIE for this test. See _.IS_EDGE for Edge (version 12+) detection.
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.