I made a simple test with first drawing one mesh of sphere(515 verts and 768 primitives) and second drawing a skybox(5040 verts and 1680 primitives).
The sphere mesh is ZWrite on and ZTest on, and the skybox is ZWrite Off and ZTest on.
Wth the streamline report, the first sphere is expected to enable the ZSUpdate, and the SkyBox is expected with EarlyZSKilled with the Sphere quads size.
Those two values are expected to be exact, as a result, the EarlyZSKilledQuads is far more different from ZSUpdateQuads.The MaliCoreQuadsEarlyZSUpdatedQuads is almost close to the expectation, but the EarlyZSKilledQuads with 20,949.
I wonder how the EarlyZSKilledQuads is calculated.