Comment by throwaway_se099

> Oddly, the linked keyboard doesn't appear to have a tab key but the Vi source code you found contains them? Am I missing something obvious?

Vi has the insert-mode commands for indenting (Ctrl-T) and unindenting (Ctrl-D) the current line. If you're used to them, you don't really need Tab except for aligning things within the line. Also, Tab is Ctrl-I.