And below that: "To select a series of individual cells, use a front end token such as "SelectNextLine":". So I suppose there may not be further alternatives
So SelectNextLine is probably what shift+downarrow does
Item[KeyEvent["Down", Modifiers -> {Shift}], "SelectNextLine"] is in KeyEventTranslations.tr
Ah yeah sure, I think the question is acceptable.
@William but maybe I should have asked: Why are you trying to select all output cells? What do you want to do that you cannot do programatically by manipulating CellObjects?
@William I have to go now, sorry. Good luck with this!