Managed to get on top of the wall before fighting the bird (by jumping from the statue)
You die when you fall down, and it's not possible to get to the bridge, so it can't be used for sequence breaking. Did manage to get slightly further down though
In the final chapter, if you jump down to the dead orb-walking thingy + bird, you can sometimes trigger the respawn point down there.
I'm not completely sure what triggers it, but I think it has to do with landing in the part that's partially inside the wall. It might be slightly higher or something
Though after that, you get stuck down there, so you have to reload from the last checkpoint to get up
It's also possible to get on top of this small plateu near the statue that's clockwise to the starting-statue.
Originally thought it might be a place they hid one of the secrets I haven't found because of the door-like shape, and the pillars that seem like they're placed to be jumped on, but since you can't grab them on the side, and it's hard to move to the secound plateu (and I think impossible to get to the rest), it's definitely not.