Internet Explorer

Internet Explorer was the default browser for Windows XP. It is now entirely useless as it dosen't support modern TLS. Even if you did the POSReady hacks, the rendering engine can't cope with HTML5 and most modern websites actively block Internet Explorer.

Version 6
The most infamous version which was used for years after it was obsolete due to being used in businesses who made proprietary web apps. Also was widely used in China and South Korea.

Version 7
Brought tabbed browsing to IE. Was heavily influenced by the success of Firefox.

Version 8
Last version of IE for XP. Was three versions behind Windows 7 and 8.1 when XP support ended. Microsoft’s lack of development of IE saw them eventually abandon their own browser engine for a Chromium based one in later Windows versions.

TLS 1.1/1.2 support (no elliptic-curve support)
Install KB4019276 for POSReady 2009 from the Microsoft Update Catalogue site, and then install any IE8 cumulative update for Windows XP/POSReady 2009 from January 2017 onwards.

After a reboot, open in regedit to the key HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Internet Explorer\AdvancedOptions\CRYPTO and delete or blank out 'OSVersion' from the TLS11 and TLS12 subkeys.

Shell browsers
Due to the IE engine being embeddable it was widely used in shell browsers which used it as an ActiveX control. Common features were adding tabbed browsing before IE got native tabbed browsing. There was also the reverse with Chrome frame where Google Chrome was embbeded within Internet Explorer.