The description of the the GM's role in the PHB (around p 8 or 9).I'd like to ask what 4e texts support this style of play?
The stuff on player-authored quests (in the PHB and DMG).
All the stuff in the PHB and DMG that presents play in terms of encounters (either combat or skill challenge; there is also a nod to puzzles), plus the mechanics that support this (short rest recovery, the general absence of durations and healing times and the like that get in the way of framing scenes and treating the scene/encounter as the basic unit of play).
The tight relationship between encounters, XP earned, levels gained and hence treasure parcels collected (which also allows a complete decoupling of treasure from looting): these allow the game to be approached in a scene-framed fashion without anyone needing to worry about how that will impact progression, rewards etc.
The capacity the PC builds give to impact the fiction, especially via choices about when to "go all out" (daily powers; action points).
The approach to setting, which focuses on key tropes, themes and concepts (the ancient empires, ancient rivalries, the Dawn War, etc, etc), which anticipates DW's "draw maps, leave blanks".
Probably other stuff too, but the above is a start.