On my machine, mapping Ctrl← ends up deleting lines in both insert as well as normal mode. I tried to find where exactly these mappings were being sourced from:
:verbose map <C-Left>,
:verbose imap <C-Left> and
:verbose nmap <C-Left> and all of them returned
No mapping found. If no mapping was found, why does any change occur to the buffer at all on issuing this sequence of key strokes?
How can I find out the source of this action for the keyboard shortcut?
As suggested in the comments,
abc|def (cursor after
c in insert mode) followed by CtrlvCtrl← ends up giving: