[hexadecimated]

Before Ctrl+C and Ctrl+V to copy and paste, the usual method was Ctrl+Ins and Shift+Ins (and Shift+Del for cut), so this key did have a lot of use back in the day. These key combinations still work in most Windows software.

[int_19h]

In DOS, these combos were used by Borland's Turbo Vision GUI toolkit (and they didn't offer Ctrl+C/V/X as alternatives). So everything written using that - and there was quite a bit, especially once you count LOB apps - had those shortcuts. In particular, all of Borland's own IDEs did, so those of us who learned to code C or Pascal on DOS in that era still got those shortcuts memorized.

[taco_emoji]

I use those combos when mousing left-handed (I'm right-handed, but ambidextrous with the mouse due to RSI issues).