SRP detection fails with removed HDRP 6000.2.x
even when hdrp is disabled and removed, GraphicsSettings.asset contains this row
m_RenderPipelineGlobalSettingsMap: UnityEngine.Rendering.HighDefinition.HDRenderPipeline: {fileID: 11400000, guid: ....., type: 2}
its only removed if you do Reset on Project Settings/Graphics panel.. probably unity bug.
reported as a bug, lets see.. "IN-99018"
nice, accepted as a bug https://issuetracker.unity3d.com/product/unity/issues/guid/UUM-102905
but got closed "As Designed"
Resolution Notes: The links in the Graphics Settings remain pointing to the HDRP Global Settings even if the HDRP package is removed. This is because, if HDRP is restored, these references also need to be restored. This approach is consistent with the behavior of MonoBehaviours in the Scene and ScriptableObjects in general. To determine the availability of a render pipeline in the project, we recommend using the PackageInfo API. If you need to perform this check outside of the Unity project, parsing the manifest.json file located in the Packages folder would be a more suitable alternative.
in hdrp project
if hdrp is assigned, GraphicsSettings.asset has this:
m_CustomRenderPipeline: {fileID: 11400000, guid: 023a2613e70294d4f9514feb149706e0, type: 2}
if not assigned, *but need to do Save Project in unity first,
m_CustomRenderPipeline: {fileID: 0}