The dependencies of bug 1313111 are going to add toolchain dependencies, that will make build jobs start using toolchain artifacts instead of tooltool packages. AFAIK, CoT ignores the latter, but everything was put in place so that it can handle the former, as discussed in the past. Specifically: - bug 1383993 made the toolchain jobs output a CoT artifact, such as https://queue.taskcluster.net/v1/task/aVDPu2J5StCoA0SZLWIWRg/runs/0/artifacts/public/chainOfTrust.json.asc - bug 1383996 made build jobs output an artifact detailing the toolchains it downloads (including the tooltool ones), such as: https://queue.taskcluster.net/v1/task/YtJJYUuUR_y4US515f6BLQ/runs/0/artifacts/public/build/toolchains.json Note that because none of the dependencies of bug 1313111 actually migrating stuff over have landed yet, the latter artifact only contains tooltool urls, but would contain tc artifact urls as soon as e.g. bug 1384417 lands.