I noticed that over 50 minutes were spent in PreprocessSpinePrefabMeshes every time I build. We're using Unity 2020.3.32f and spine-unity-4.1-2022-07-01.
This function seems to open every prefab in the project (and dependent packages?) and scan for objects with SkeletonRenderer and MeshFilter components in order to remove shared meshes. Adding an hour to the build time in local builds is killing productivity. The feature is enabled by HAS_ON_POSTPROCESS_PREFAB but we are unable to disable it because it is forced like this