> > I feel like most of these line based commands exist

> > in other editors because they don't have Emacs' `C-k'.

> More generally, they don't have Emacs...

But even so...

If I wrote the duplicate-line-or-region, it wasn't because of any other editor having whatever... It was just because I sometimes need to duplicate things and don't want them to appear in the kill-ring.

Actually, the more I think, the more I realise how much I duplicate stuff :-)

Same goes with moving lines around, which I've also seen being talked about. Having a package is good enough for me and there's a package for that in ELPA. 

Don't need that as part of stock Emacs core either...

/PA