Ok, at least for URP it’s not so bad. Via the shader discord, Cyan told me that the tag was always UniversalPipeline, it’s just that a bug in previous versions would incorrectly also render UniversalRenderPipeline. That bug is detailed here - the renderer was ignoring filtering via the draw tag Opaque forward render pass renders shaders that are defined as incompatible w/URP
So for URP, you can have compatibility with both future and past versions - you need to change UniversalRenderPipeline to UniversalPipeline and it will work with both old and new versions (I tested on 2021). The tag value didn’t change, it just was not respected beforehand.