Question SceneCamera.RenderSelected shaders and SRPs?

So I'm currently, perhaps overoptimistically, attempting to bodge camera-relative rendering into URP (using the HDRP code/shaders as reference), due to significant geometry wobbling when inside a moving vehicle at only a couple of thousand units from the origin.

I've made some progress, but one of the many things I'm trying to fix is the outline/wireframe rendering in the scene view.

I can see from RenderDoc that SceneCamera.RenderOutline is using different shaders for HDRP - but this outline rendering seems to be internal to Unity, and not part of the scriptable render pipeline?

Does an SRP have control the behavior of this outline rendering? (Or is there some magic going on in the internals of Unity that I won't be able to control?)