Internet Explorer has a COM API which enterprise software (or worse, weird company-specific VBA scripts) can and likely does use to drive it directly. That API

Internet Explorer has a COM API which enterprise software (or worse, weird company-specific VBA scripts) can and likely does use to drive it directly. That API launches the actual iexplore.exe GUI executable and lets your code control it and interact with web pages, much like you might do with something like Selenium these days - except that this dates back to the nineties.