--- a/taskcluster/ci/legacy/tasks/branches/alder/job_flags.yml
+++ b/taskcluster/ci/legacy/tasks/branches/alder/job_flags.yml
@@ -7,15 +7,8 @@
 
 builds:
   linux64-mulet:
     platforms:
       - b2g
     types:
       opt:
         task: tasks/builds/mulet_linux.yml
-
-tests:
-  mochitest:
-    allowed_build_tasks:
-      tasks/builds/mulet_linux.yml:
-        task: tasks/tests/mulet_mochitests.yml
-        chunks: 5

--- a/taskcluster/ci/legacy/tasks/branches/base_job_flags.yml
+++ b/taskcluster/ci/legacy/tasks/branches/base_job_flags.yml
@@ -35,22 +35,16 @@ flags:
     - cppunit
     - crashtest
     - crashtest-e10s
     - external-media-tests
     - firefox-ui-functional-local
     - firefox-ui-functional-local-e10s
     - firefox-ui-functional-remote
     - firefox-ui-functional-remote-e10s
-    - gaia-build
-    - gaia-build-unit
-    - gaia-js-integration
-    - gaia-linter
-    - gaia-unit
-    - gaia-unit-oop
     - gtest
     - jittests
     - jsreftest
     - jsreftest-e10s
     - luciddream
     - marionette
     - marionette-e10s
     - marionette-webapi

--- a/taskcluster/ci/legacy/tasks/branches/base_jobs.yml
+++ b/taskcluster/ci/legacy/tasks/branches/base_jobs.yml
@@ -312,52 +312,16 @@ tests:
   firefox-ui-functional-remote-e10s:
     allowed_build_tasks:
       tasks/builds/opt_linux64.yml:
         task: tasks/tests/fx_linux64_fxui_functional_remote_e10s_opt.yml
       tasks/builds/dbg_linux64.yml:
         task: tasks/tests/fx_linux64_fxui_functional_remote_e10s_dbg.yml
       tasks/builds/opt_linux64_pgo.yml:
         task: tasks/tests/fx_linux64_fxui_functional_remote_e10s_opt.yml
-  gaia-build:
-    allowed_build_tasks:
-      tasks/builds/mulet_linux.yml:
-        task: tasks/tests/mulet_build_test.yml
-      tasks/builds/mulet_linux_dbg.yml:
-        task: tasks/tests/mulet_build_test.yml
-  gaia-build-unit:
-    allowed_build_tasks:
-      tasks/builds/mulet_linux.yml:
-        task: tasks/tests/mulet_build_unit.yml
-      tasks/builds/mulet_linux_dbg.yml:
-        task: tasks/tests/mulet_build_unit.yml
-  gaia-js-integration:
-    allowed_build_tasks:
-      tasks/builds/mulet_linux.yml:
-        task: tasks/tests/mulet_gaia_js_integration_tests.yml
-      tasks/builds/mulet_linux_dbg.yml:
-        task: tasks/tests/mulet_gaia_js_integration_tests.yml
-  gaia-linter:
-    allowed_build_tasks:
-      tasks/builds/mulet_linux.yml:
-        task: tasks/tests/mulet_linter.yml
-      tasks/builds/mulet_linux_dbg.yml:
-        task: tasks/tests/mulet_linter.yml
-  gaia-unit:
-    allowed_build_tasks:
-      tasks/builds/mulet_linux.yml:
-        task: tasks/tests/mulet_gaia_unit.yml
-      tasks/builds/mulet_linux_dbg.yml:
-        task: tasks/tests/mulet_gaia_unit.yml
-  gaia-unit-oop:
-    allowed_build_tasks:
-      tasks/builds/mulet_linux.yml:
-        task: tasks/tests/mulet_gaia_unit_oop.yml
-      tasks/builds/mulet_linux_dbg.yml:
-        task: tasks/tests/mulet_gaia_unit_oop.yml
   gtest:
     allowed_build_tasks:
       tasks/builds/opt_linux64.yml:
         task: tasks/tests/fx_linux64_gtest_opt.yml
       tasks/builds/dbg_linux64.yml:
         task: tasks/tests/fx_linux64_gtest_dbg.yml
       tasks/builds/opt_linux64_pgo.yml:
         task: tasks/tests/fx_linux64_gtest_opt.yml
@@ -414,20 +378,16 @@ tests:
       tasks/builds/dbg_linux64.yml:
         task: tasks/tests/fx_linux64_marionette_e10s_dbg.yml
       tasks/builds/opt_linux64_pgo.yml:
         task: tasks/tests/fx_linux64_marionette_e10s_opt.yml
       tasks/builds/opt_linux64-asan.yml:
         task: tasks/tests/fx_linux64_marionette_e10s_opt.yml
   mochitest:
     allowed_build_tasks:
-      tasks/builds/mulet_linux.yml:
-        task: tasks/tests/mulet_mochitests.yml
-      tasks/builds/mulet_linux_dbg.yml:
-        task: tasks/tests/mulet_mochitests.yml
       tasks/builds/opt_linux64.yml:
         task: tasks/tests/fx_linux64_mochitest_plain_opt.yml
       tasks/builds/dbg_linux64.yml:
         task: tasks/tests/fx_linux64_mochitest_plain_dbg.yml
       tasks/builds/opt_linux64_pgo.yml:
         task: tasks/tests/fx_linux64_mochitest_plain_opt.yml
       tasks/builds/opt_linux64-asan.yml:
         task: tasks/tests/fx_linux64_mochitest_plain_opt.yml
@@ -608,20 +568,16 @@ tests:
       tasks/builds/dbg_linux64.yml:
         task: tasks/tests/fx_linux64_mochitest_clipboard_e10s_dbg.yml
       tasks/builds/opt_linux64_pgo.yml:
         task: tasks/tests/fx_linux64_mochitest_clipboard_e10s_opt.yml
       tasks/builds/opt_linux64-asan.yml:
         task: tasks/tests/fx_linux64_mochitest_clipboard_e10s_opt.yml
   reftest:
     allowed_build_tasks:
-      tasks/builds/mulet_linux.yml:
-        task: tasks/tests/mulet_reftests.yml
-      tasks/builds/mulet_linux_dbg.yml:
-        task: tasks/tests/mulet_reftests.yml
       tasks/builds/opt_linux64.yml:
         task: tasks/tests/fx_linux64_reftest_opt.yml
       tasks/builds/dbg_linux64.yml:
         task: tasks/tests/fx_linux64_reftest_dbg.yml
       tasks/builds/opt_linux64_pgo.yml:
         task: tasks/tests/fx_linux64_reftest_opt.yml
       tasks/builds/android_api_15.yml:
         task: tasks/tests/fx_android-api-15_reftest_opt.yml

--- a/taskcluster/ci/legacy/tasks/branches/mozilla-central/job_flags.yml
+++ b/taskcluster/ci/legacy/tasks/branches/mozilla-central/job_flags.yml
@@ -23,39 +23,13 @@ builds:
     platforms:
       - b2g
     types:
       opt:
         task: tasks/builds/b2g_nexus_5l_eng.yml
       debug:
         task: tasks/builds/b2g_nexus_5l_debug.yml
 
-tests:
-  gaia-build:
-    allowed_build_tasks:
-      tasks/builds/mulet_linux.yml:
-        task: tasks/tests/mulet_build_test.yml
-  gaia-build-unit:
-    allowed_build_tasks:
-      tasks/builds/mulet_linux.yml:
-        task: tasks/tests/mulet_build_unit.yml
-  gaia-js-integration:
-    allowed_build_tasks:
-      tasks/builds/mulet_linux.yml:
-        task: tasks/tests/mulet_gaia_js_integration_tests.yml
-  gaia-linter:
-    allowed_build_tasks:
-      tasks/builds/mulet_linux.yml:
-        task: tasks/tests/mulet_linter.yml
-  gaia-unit:
-    allowed_build_tasks:
-      tasks/builds/mulet_linux.yml:
-        task: tasks/tests/mulet_gaia_unit.yml
-  gaia-unit-oop:
-    allowed_build_tasks:
-      tasks/builds/mulet_linux.yml:
-        task: tasks/tests/mulet_gaia_unit_oop.yml
-
 post-build:
   simulator:
     allowed_build_tasks:
       - tasks/builds/mulet_linux.yml
     task: tasks/post-builds/mulet_simulator.yml

deleted file mode 100644
--- a/taskcluster/ci/legacy/tasks/tests/b2g_unittest_base.yml
+++ /dev/null
@@ -1,32 +0,0 @@
----
-$inherits:
-  from: 'tasks/docker_test.yml'
-task:
-  scopes:
-    - 'docker-worker:cache:level-{{level}}-{{project}}-tc-vcs'
-    - 'docker-worker:cache:level-{{level}}-{{project}}-dotcache'
-    - 'docker-worker:capability:device:loopbackVideo'
-    - 'docker-worker:capability:device:loopbackAudio'
-  payload:
-    cache:
-      # So pip installs are cached...
-      level-{{level}}-{{project}}-dotcache: /home/worker/.cache
-      level-{{level}}-{{project}}-tc-vcs: '/home/worker/.tc-vcs'
-    capabilities:
-      devices:
-        loopbackVideo: true
-        loopbackAudio: true
-    env:
-      NEED_XVFB: true
-      GECKO_HEAD_REPOSITORY: '{{{head_repository}}}'
-      GECKO_HEAD_REV: '{{{head_rev}}}'
-      GAIA_HEAD_REPOSITORY: '{{{gaia_head_repository}}}'
-      GAIA_BASE_REPOSITORY: '{{{gaia_base_repository}}}'
-      GAIA_REF: '{{{gaia_ref}}}'
-      GAIA_REV: '{{{gaia_rev}}}'
-    artifacts:
-      'public/build':
-        type: directory
-        path: '/home/worker/artifacts/'
-        expires:
-          relative-datestamp: '1 year'

deleted file mode 100644
--- a/taskcluster/ci/legacy/tasks/tests/mulet_build_test.yml
+++ /dev/null
@@ -1,29 +0,0 @@
----
-$inherits:
-  from: 'tasks/tests/b2g_unittest_base.yml'
-task:
-  metadata:
-    name: '[TC] - Gaia Build Test'
-    description: Gaia Build Test test run
-
-  payload:
-    env:
-      NEED_PULL_GAIA: true
-      MOZHARNESS_SCRIPT: 'mozharness/scripts/gaia_build_integration.py'
-      MOZHARNESS_CONFIG: 'mozharness/configs/b2g/taskcluster_gaia_integration.py'
-    command:
-      - bash
-      - /home/worker/bin/test.sh
-      - --application=firefox
-      - {"task-reference": "--installer-url=https://queue.taskcluster.net/v1/task/<{{build_slugid}}>/artifacts/{{build_location}}"}
-      - {"task-reference": "--test-packages-url=https://queue.taskcluster.net/v1/task/<{{build_slugid}}>/artifacts/{{test_packages_location}}"}
-      - --xre-url=https://api.pub.build.mozilla.org/tooltool/sha512/cefa8c00db04969d3a50e2a5509bd4ea1dc17d256a651a9518cb28dad72e87a1dbbcd3c88ef770be0edf0ab73d2d73925140df93618ffb7fab81b789d312f547
-
-  extra:
-    treeherderEnv:
-      - production
-      - staging
-    treeherder:
-      groupSymbol: "?"
-      symbol: 'Gb'
-      productName: b2g

deleted file mode 100644
--- a/taskcluster/ci/legacy/tasks/tests/mulet_build_unit.yml
+++ /dev/null
@@ -1,28 +0,0 @@
----
-$inherits:
-  from: 'tasks/tests/b2g_unittest_base.yml'
-task:
-  metadata:
-    name: '[TC] - Gaia Build Unit Test'
-    description: Gaia Build Unit Test
-
-  payload:
-    env:
-      NEED_PULL_GAIA: true
-      MOZHARNESS_SCRIPT: 'mozharness/scripts/gaia_build_unit.py'
-      MOZHARNESS_CONFIG: 'mozharness/configs/b2g/taskcluster_gaia_integration.py'
-    command:
-      - bash
-      - /home/worker/bin/test.sh
-      - --application=firefox
-      - {"task-reference": "--installer-url=https://queue.taskcluster.net/v1/task/<{{build_slugid}}>/artifacts/{{build_location}}"}
-      - {"task-reference": "--test-packages-url=https://queue.taskcluster.net/v1/task/<{{build_slugid}}>/artifacts/{{test_packages_location}}"}
-
-  extra:
-    treeherderEnv:
-      - production
-      - staging
-    treeherder:
-      groupSymbol: "?"
-      symbol: 'Gbu'
-      productName: b2g

deleted file mode 100644
--- a/taskcluster/ci/legacy/tasks/tests/mulet_gaia_js_integration_tests.yml
+++ /dev/null
@@ -1,34 +0,0 @@
----
-$inherits:
-  from: 'tasks/tests/b2g_unittest_base.yml'
-reruns: 3
-task:
-  metadata:
-    name: '[TC] Mulet Gaia JS Integration Test'
-    description: Mulet Gaia JS Integration Test run {{chunk}}
-
-  payload:
-    env:
-      NEED_PULL_GAIA: true
-      MOZHARNESS_SCRIPT: 'mozharness/scripts/gaia_integration.py'
-      MOZHARNESS_CONFIG: 'mozharness/configs/b2g/taskcluster_gaia_integration.py'
-    command:
-      - bash
-      - /home/worker/bin/test.sh
-      - --application=firefox
-      - {"task-reference": "--installer-url=https://queue.taskcluster.net/v1/task/<{{build_slugid}}>/artifacts/{{build_location}}"}
-      - {"task-reference": "--test-packages-url=https://queue.taskcluster.net/v1/task/<{{build_slugid}}>/artifacts/{{test_packages_location}}"}
-      - --total-chunk={{total_chunks}}
-      - --this-chunk={{chunk}}
-
-  extra:
-    chunks:
-      total: 10
-    treeherderEnv:
-      - production
-      - staging
-    treeherder:
-      groupName: Gaia JS Integration Test
-      groupSymbol: Gij
-      symbol: '{{chunk}}'
-      productName: b2g

deleted file mode 100644
--- a/taskcluster/ci/legacy/tasks/tests/mulet_gaia_unit.yml
+++ /dev/null
@@ -1,33 +0,0 @@
----
-$inherits:
-  from: 'tasks/tests/b2g_unittest_base.yml'
-task:
-  metadata:
-    name: '[TC] Mulet Gaia Unit Test'
-    description: Mulet Gaia Unit Test
-
-  payload:
-    env:
-      NEED_PULL_GAIA: true
-      MOZHARNESS_SCRIPT: 'mozharness/scripts/gaia_unit.py'
-      MOZHARNESS_CONFIG: 'mozharness/configs/b2g/taskcluster_gaia_unit_production.py'
-    command:
-      - bash
-      - /home/worker/bin/test.sh
-      - --application=firefox
-      - {"task-reference": "--installer-url=https://queue.taskcluster.net/v1/task/<{{build_slugid}}>/artifacts/{{build_location}}"}
-      - {"task-reference": "--test-packages-url=https://queue.taskcluster.net/v1/task/<{{build_slugid}}>/artifacts/{{test_packages_location}}"}
-      - --xre-url=https://api.pub.build.mozilla.org/tooltool/sha512/cefa8c00db04969d3a50e2a5509bd4ea1dc17d256a651a9518cb28dad72e87a1dbbcd3c88ef770be0edf0ab73d2d73925140df93618ffb7fab81b789d312f547
-      - --total-chunk={{total_chunks}}
-      - --this-chunk={{chunk}}
-
-  extra:
-    treeherderEnv:
-      - production
-      - staging
-    chunks:
-      total: 10
-    treeherder:
-      groupSymbol: Gu
-      groupName: Mulet gaia unit tests
-      symbol: {{chunk}}

deleted file mode 100644
--- a/taskcluster/ci/legacy/tasks/tests/mulet_gaia_unit_oop.yml
+++ /dev/null
@@ -1,33 +0,0 @@
----
-$inherits:
-  from: 'tasks/tests/b2g_unittest_base.yml'
-task:
-  metadata:
-    name: '[TC] Mulet Gaia Unit Test OOP'
-    description: Mulet Gaia Unit Test OOP
-
-  payload:
-    env:
-      NEED_PULL_GAIA: true
-      MOZHARNESS_SCRIPT: 'mozharness/scripts/gaia_unit.py'
-      MOZHARNESS_CONFIG: 'mozharness/configs/b2g/taskcluster_gaia_unit_production.py'
-    command:
-      - bash
-      - /home/worker/bin/test.sh
-      - --application=firefox
-      - --browser-arg=-oop
-      - {"task-reference": "--installer-url=https://queue.taskcluster.net/v1/task/<{{build_slugid}}>/artifacts/{{build_location}}"}
-      - {"task-reference": "--test-packages-url=https://queue.taskcluster.net/v1/task/<{{build_slugid}}>/artifacts/{{test_packages_location}}"}
-      - --xre-url=https://api.pub.build.mozilla.org/tooltool/sha512/cefa8c00db04969d3a50e2a5509bd4ea1dc17d256a651a9518cb28dad72e87a1dbbcd3c88ef770be0edf0ab73d2d73925140df93618ffb7fab81b789d312f547
-      - --total-chunk={{total_chunks}}
-      - --this-chunk={{chunk}}
-
-  extra:
-    treeherderEnv:
-      - staging
-    chunks:
-      total: 10
-    treeherder:
-      groupSymbol: Gu-oop
-      groupName: Mulet Gaia unit tests OOP
-      symbol: {{chunk}}

deleted file mode 100644
--- a/taskcluster/ci/legacy/tasks/tests/mulet_linter.yml
+++ /dev/null
@@ -1,28 +0,0 @@
----
-$inherits:
-  from: 'tasks/tests/b2g_unittest_base.yml'
-task:
-  metadata:
-    name: '[TC] - Gaia Linter'
-    description: Linter Test
-
-  payload:
-    env:
-      NEED_PULL_GAIA: true
-      MOZHARNESS_SCRIPT: 'mozharness/scripts/gaia_linter.py'
-      MOZHARNESS_CONFIG: 'mozharness/configs/b2g/taskcluster_gaia_integration.py'
-    command:
-      - bash
-      - /home/worker/bin/test.sh
-      - --application=firefox
-      - {"task-reference": "--installer-url=https://queue.taskcluster.net/v1/task/<{{build_slugid}}>/artifacts/{{build_location}}"}
-      - {"task-reference": "--test-packages-url=https://queue.taskcluster.net/v1/task/<{{build_slugid}}>/artifacts/{{test_packages_location}}"}
-
-  extra:
-    treeherderEnv:
-      - production
-      - staging
-    treeherder:
-      groupSymbol: "?"
-      symbol: 'Li'
-      productName: 'b2g'

deleted file mode 100644
--- a/taskcluster/ci/legacy/tasks/tests/mulet_mochitests.yml
+++ /dev/null
@@ -1,36 +0,0 @@
----
-$inherits:
-  from: 'tasks/tests/b2g_unittest_base.yml'
-task:
-  metadata:
-    name: '[TC] Mulet Mochitests ( {{chunk}} )'
-    description: Mulet Mochitest run {{chunk}}
-
-  payload:
-    env:
-      NEED_PULSEAUDIO: true
-      MOZHARNESS_SCRIPT: 'mozharness/scripts/desktop_unittest.py'
-      MOZHARNESS_CONFIG: >
-        mozharness/configs/unittests/linux_unittest.py
-        mozharness/configs/remove_executables.py
-    command:
-      - bash
-      - /home/worker/bin/test.sh
-      - --no-read-buildbot-config
-      - {"task-reference": "--installer-url=https://queue.taskcluster.net/v1/task/<{{build_slugid}}>/artifacts/{{build_location}}"}
-      - {"task-reference": "--test-packages-url=https://queue.taskcluster.net/v1/task/<{{build_slugid}}>/artifacts/{{test_packages_location}}"}
-      - --download-symbols=ondemand
-      - --mochitest-suite=plain-chunked
-      - --total-chunk={{total_chunks}}
-      - --this-chunk={{chunk}}
-
-  extra:
-    treeherderEnv:
-      - production
-      - staging
-    chunks:
-      total: 5
-    treeherder:
-      groupSymbol: M
-      groupName: Mulet mochitests
-      symbol: {{chunk}}

deleted file mode 100644
--- a/taskcluster/ci/legacy/tasks/tests/mulet_reftests.yml
+++ /dev/null
@@ -1,36 +0,0 @@
----
-$inherits:
-  from: 'tasks/tests/b2g_unittest_base.yml'
-task:
-  metadata:
-    name: '[TC] Mulet Reftest ( {{chunk}} )'
-    description: Mulet Reftest run {{chunk}}
-
-  payload:
-    env:
-      MOZ_DISABLE_NONLOCAL_CONNECTIONS: 0
-      NEED_PULL_GAIA: true
-      MOZHARNESS_SCRIPT: 'mozharness/scripts/mulet_unittest.py'
-      MOZHARNESS_CONFIG: 'mozharness/configs/b2g/taskcluster_mulet_automation.py'
-    command:
-      - bash
-      - /home/worker/bin/test.sh
-      - {"task-reference": "--installer-url=https://queue.taskcluster.net/v1/task/<{{build_slugid}}>/artifacts/{{build_location}}"}
-      - {"task-reference": "--test-packages-url=https://queue.taskcluster.net/v1/task/<{{build_slugid}}>/artifacts/{{test_packages_location}}"}
-      - --test-suite=reftest
-      - --test-manifest=tests/layout/reftests/reftest.list
-      - --this-chunk={{chunk}}
-      - --total-chunk={{total_chunks}}
-
-  extra:
-    treeherderEnv:
-      - production
-      - staging
-    chunks:
-      total: 6
-    treeherder:
-      groupSymbol: R
-      groupName: Mulet Reftest
-      symbol: 'R{{chunk}}'
-      productName: b2g
-      tier: 3