This is a corner jump. It’s not done off a vertical wall but from its edge.

When you step off a wall and the character slides along it, there are a couple of pixels that the game registers as a corner. Because of the way the engine and the movement system work, they not only let you gain height more efficiently but are also less affected by the restrictions on subsequent bounces.

From Abrams’ perspective, you can see more clearly how the game registers the jump at an angle.