Repo level prebuilt detection is not reliable and is a maintenance burden. With the UB Flat Flow, we believe the best course of action is to remove repo level prebuilt detection. Repo devs can utilize the optional VMR SB validation leg else prebuilts will get caught in the forward flow PRs.

There is value in leaving the prebuilt detection in place until the flat flow is enabled. During the flat flow enablement, we should have an easy way to disable the detection. Once the flat flow is proven, we can permanently remove the repro level prebuilt infrastructure. Note the repo level prebuilt detection is a largely a separate implementation from the source build product level prebuilt detection.

At the repo level, the prebuilt baseline (eng/SourceBuildPrebuiltBaseline.xml) should be removed along with all of the source build intermediate dependencies declares in the Version.Details.xml.