testing/taskcluster/tasks/tests/b2g_emulator_xpcshell_chunked.yml contains --xre-url https://queue.taskcluster.net/v1/task/wXAHAaxDQpqxoWF1iljJjg/runs/0/artifacts/public/cache/xulrunner-sdk-40.zip which refers to a task that expires in May. Incidentally, this old task has a newline in its scopes and thus can't be viewed: Jan 13 12:46:45 taskcluster-queue app/web.6: Wed, 13 Jan 2016 20:46:44 GMT base:api Reply for /task/wXAHAaxDQpqxoWF1iljJjg didn't match schema: http://schemas.taskcluster.net/queue/v1/task.json# got errors: {"validation":{"scopes":{"schema":{"2":{"pattern":true}}}}} from output: {"provisionerId":"aws-provisioner-v1","workerType":"gaia","schedulerId":"task-graph-scheduler","taskGroupId":"v_3ginoXR5q8aHKpmGwVBA","routes":["tc-treeherder.gaia.42b9549e14914c6967401bca2fdebf7a326b7733"],"priority":"normal","retries":5,"created":"2015-05-05T16:33:35.742Z","deadline":"2015-05-06T16:33:35.742Z","expires":"2016-05-06T16:33:35.742Z","scopes":["docker-worker:cache:gaia-misc-caches","docker-worker:image:quay.io/mozilla/gaia-taskenv:*","docker-worker:image:taskcluster/gaia-taskenv\n*"],"payload":{"image":"quay.io/mozilla/gaia-taskenv:0.8.9","env":{"NODE_MODULES_SRC":"npm-cache","CI":"true","GITHUB_PULL_REQUEST":"1","GITHUB_BASE_REPO":"gaia","GITHUB_BASE_USER":"mozilla-b2g","GITHUB_BASE_GIT":"https://github.com/mozilla-b2g/gaia","GITHUB_BASE_REV":"ba860ac479a07bb0265a23d210f62447e872b4fe","GITHUB_BASE_BRANCH":"master","GITHUB_HEAD_REPO":"gaia","GITHUB_HEAD_USER":"lightsofapollo","GITHUB_HEAD_GIT":"https://github.com/lightsofapollo/gaia","GITHUB_HEAD_REV":"42b9549e14914c6967401bca2fdebf7a326b7733","GITHUB_HEAD_BRANCH":"dostuff","TREEHERDER_PROJECT":"gaia","TREEHERDER_REVISION":"42b9549e14914c6967401bca2fdebf7a326b7733"},"cache":{"gaia-misc-caches":"/home/tester/caches/"},"command":["entrypoint","mkdir -p /home/tester/git_checkout/artifacts && curl https://s3-us-west-2.amazonaws.com/test-caching/xulrunner-sdk-40.zip > /home/tester/git_checkout/artifacts/xulrunner-sdk-40.zip"],"artifacts":{"public/cache":{"type":"directory","path":"/home/tester/git_checkout/artifacts/","expires":"2016-05-05T16:33:35.723Z"}},"maxRunTime":1800},"metadata":{"name":"Gaia JSON Lint","description":"JSON linter","source":"http://todo.com/soon","owner":"dev-gaia@lists.mozilla.org"},"tags":{},"extra":{"treeherder":{"symbol":"JSON","groupSymbol":"LINT","groupName":"Linters"}}} I don't know who owns that task type, but it should probably be hooked up to something that can either find or schedule a xulrunner build, or just download xulrunner from tooltool or something instead.