The 'IT Department' (remember this is a small golf car repair shop/custom shop) is that idiot 'super computer guy' (local business doing contract work). He installed the PC (replacing a stolen Vista machine), installed the 'fake' antivirus and 'alternative' search engine (a knockoff Google clone--pulls up some, rather **cough** 'interesting' results) and the UNV IP camera system (hardwired of course). The IP cameras run off of a PC (running a proprietary OS, and DVR server) that uses a small intranet address (doesn't use the actual internet, just an http address) to host a website that runs off the system which our work PC pulls up via IE. It's not even https, just http. It requires whatever version of Flash Player that IE 11 supported. Any attempt to open another browser (before it got blacklisted) would change the default web handler making that DVR website try to open in Chrome or Edge thus breaking things, since neither would open the site claiming a 'unsupported plugin' isn't installed. Clicking on the 'learn more' produces an Adobe page explaining the death of Flash.
When it gets auto-updated to Windows 11, unless he managed to blacklist the auto updates, things will indeed get interesting. I haven't seen any indication that auto updates are enabled, since I never get to see the little 'windows logo red dot' indicating that updates are pending. The start menu/taskbar is all white (I think the GPU driver crashes daily) and Cortana still exists on the taskbar (she's an icon in more recent updated builds) as a full blown 'ask me anything' field. I think it's a 2017 release? I don't bother with it unless I absolutely have to. I got a better parts database on a TI graphing calculator that I programmed myself. Dead serious here. I hate that PC. I would get a picture of it, when it's actually working but there's a lot of shortcuts with personal details that I'd get into trouble by uploading to the internet. It's a mess. Literally a hundred or so desktop shortcuts to various websites, documents, banking info splattered across two monitors, the second usually showing the IP camera views in IE full-screen while the first monitor has Yahoo! Mail (why?) and usually an Excel 2010 spreadsheet open to contacts view. While you cannot open Chrome or Edge directly, you can access them by double-clicking say the Yahoo! icon on the desktop.
As for other obsolete tech still in operation, many PoS terminals at gas stations run on Windows XP (titled Server 2002) and many ATMs have XP embedded. A bit of interesting trivia, many of those PoS terminals make Sonic sound effects like the ring grab sound or the ring lost sound when scanning/bad scan results. Also you hear Sonic 'spring bumper' noises when someone pre-auth's a gas pump. Not sure how that didn't get a lawsuit from Sega but many Kangaroo Express stations use them.
As for another browser, her favorite IT guy disabled the admin account, and you cannot install 'Foxfire' as she calls it on there even if you tried.