Timeline negative keyframe position [<0]

Timeline change proposition. While working on bigger animation chunks which length changes in time [like in production], its nice to keep animation start at 0 at all cost, and not to "hack" it via moving animation at yolo count of frames to the right. It would be nice to move keyframes out of the "working area" even in negative frames.. left from the 0. All this non linear action interpolation would be much more nicer and kind of feature would bring benefit in few angles. Clean source files, clean timestamp management, easier manipulation, cause I wouldn't need to move all my 728 layers, etc..
Blender owns this kind of smoothly. https://i.imgur.com/X0wlzPp.png