diff --git a/browser/components/migration/moz.build b/browser/components/migration/moz.build
index b2088fafe24c..8c958ab7d4d4 100644
--- a/browser/components/migration/moz.build
+++ b/browser/components/migration/moz.build
@@ -6,7 +6,7 @@
 
 XPCSHELL_TESTS_MANIFESTS += ["tests/unit/xpcshell.toml"]
 
-MARIONETTE_UNIT_MANIFESTS += ["tests/marionette/manifest.toml"]
+MARIONETTE_MANIFESTS += ["tests/marionette/manifest.toml"]
 
 MOCHITEST_CHROME_MANIFESTS += ["tests/chrome/chrome.toml"]
 
diff --git a/browser/components/moz.build b/browser/components/moz.build
index 88301045a66d..b396303b132e 100644
--- a/browser/components/moz.build
+++ b/browser/components/moz.build
@@ -111,4 +111,6 @@ if CONFIG["MOZ_UPDATER"]:
         "tests/browser/whats_new_page/browser.toml",
     ]
 
+MARIONETTE_MANIFESTS += ["tests/marionette/manifest.toml"]
+
 XPCSHELL_TESTS_MANIFESTS += ["tests/unit/xpcshell.toml"]
diff --git a/browser/components/places/moz.build b/browser/components/places/moz.build
index 6f41de098aff..496e83089db0 100644
--- a/browser/components/places/moz.build
+++ b/browser/components/places/moz.build
@@ -12,6 +12,7 @@ BROWSER_CHROME_MANIFESTS += [
     "tests/browser/browser.toml",
     "tests/browser/interactions/browser.toml",
 ]
+MARIONETTE_MANIFESTS += ["tests/marionette/manifest.toml"]
 
 JAR_MANIFESTS += ["jar.mn"]
 
diff --git a/browser/components/search/moz.build b/browser/components/search/moz.build
index 104ac3ae24ab..9f89090aa2d7 100644
--- a/browser/components/search/moz.build
+++ b/browser/components/search/moz.build
@@ -17,7 +17,7 @@ BROWSER_CHROME_MANIFESTS += [
     "test/browser/telemetry/browser.toml",
 ]
 
-MARIONETTE_UNIT_MANIFESTS += ["test/marionette/manifest.toml"]
+MARIONETTE_MANIFESTS += ["test/marionette/manifest.toml"]
 
 XPCSHELL_TESTS_MANIFESTS += ["test/unit/xpcshell.toml"]
 
diff --git a/browser/components/sessionstore/moz.build b/browser/components/sessionstore/moz.build
index 11715411e704..15368267331d 100644
--- a/browser/components/sessionstore/moz.build
+++ b/browser/components/sessionstore/moz.build
@@ -6,6 +6,7 @@
 
 XPCSHELL_TESTS_MANIFESTS += ["test/unit/xpcshell.toml"]
 BROWSER_CHROME_MANIFESTS += ["test/browser.toml"]
+MARIONETTE_MANIFESTS += ["test/marionette/manifest.toml"]
 
 JAR_MANIFESTS += ["jar.mn"]
 
diff --git a/dom/cache/moz.build b/dom/cache/moz.build
index 072647c0042a..5fb5704e526a 100644
--- a/dom/cache/moz.build
+++ b/dom/cache/moz.build
@@ -95,6 +95,8 @@ BROWSER_CHROME_MANIFESTS += [
     "test/browser/browser.toml",
 ]
 
+MARIONETTE_MANIFESTS += ["test/marionette/manifest.toml"]
+
 XPCSHELL_TESTS_MANIFESTS += [
     "test/xpcshell/xpcshell.toml",
 ]
diff --git a/dom/indexedDB/moz.build b/dom/indexedDB/moz.build
index d1857f385055..1dbd0aedd926 100644
--- a/dom/indexedDB/moz.build
+++ b/dom/indexedDB/moz.build
@@ -17,6 +17,8 @@ BROWSER_CHROME_MANIFESTS += ["test/browser.toml"]
 
 MOCHITEST_CHROME_MANIFESTS += ["test/chrome.toml"]
 
+MARIONETTE_MANIFESTS += ["test/marionette/manifest.toml"]
+
 XPCSHELL_TESTS_MANIFESTS += [
     "test/unit/xpcshell-child-process.toml",
     "test/unit/xpcshell-parent-process.toml",
diff --git a/dom/quota/test/moz.build b/dom/quota/test/moz.build
index d549fa6088ff..c01a46c55205 100644
--- a/dom/quota/test/moz.build
+++ b/dom/quota/test/moz.build
@@ -8,6 +8,8 @@ TEST_DIRS += ["gtest"]
 
 BROWSER_CHROME_MANIFESTS += ["browser/browser.toml"]
 
+MARIONETTE_MANIFESTS += ["marionette/manifest.toml"]
+
 MOCHITEST_MANIFESTS += ["mochitest/mochitest.toml"]
 
 XPCSHELL_TESTS_MANIFESTS += [
@@ -82,7 +84,3 @@ TESTING_JS_MODULES.dom.quota.test.modules.worker += [
     "modules/system/worker/Utils.js",
     "modules/system/worker/UtilsChild.js",
 ]
-
-MARIONETTE_UNIT_MANIFESTS += [
-    "marionette/manifest.toml",
-]
diff --git a/dom/workers/moz.build b/dom/workers/moz.build
index 9499f47a8ade..c7818826d186 100644
--- a/dom/workers/moz.build
+++ b/dom/workers/moz.build
@@ -107,6 +107,8 @@ MOCHITEST_CHROME_MANIFESTS += [
     "test/chrome.toml",
 ]
 
+MARIONETTE_MANIFESTS += ["test/marionette/manifest.toml"]
+
 XPCSHELL_TESTS_MANIFESTS += ["test/xpcshell/xpcshell.toml"]
 
 BROWSER_CHROME_MANIFESTS += ["test/browser.toml"]
diff --git a/extensions/pref/autoconfig/moz.build b/extensions/pref/autoconfig/moz.build
index 876b1d3a8643..06b400924eba 100644
--- a/extensions/pref/autoconfig/moz.build
+++ b/extensions/pref/autoconfig/moz.build
@@ -8,4 +8,4 @@ DIRS += ["src"]
 
 XPCSHELL_TESTS_MANIFESTS += ["test/unit/xpcshell.toml", "test/unit/xpcshell_snap.toml"]
 
-MARIONETTE_UNIT_MANIFESTS += ["test/marionette/manifest.toml"]
+MARIONETTE_MANIFESTS += ["test/marionette/manifest.toml"]
diff --git a/layout/base/moz.build b/layout/base/moz.build
index 5d19c31a8727..68d70bad312f 100644
--- a/layout/base/moz.build
+++ b/layout/base/moz.build
@@ -183,6 +183,6 @@ IPDL_SOURCES += [
 FINAL_LIBRARY = "xul"
 
 BROWSER_CHROME_MANIFESTS += ["tests/browser.toml"]
-MARIONETTE_LAYOUT_MANIFESTS += ["tests/marionette/manifest.toml"]
+MARIONETTE_MANIFESTS += ["tests/marionette/manifest.toml"]
 MOCHITEST_MANIFESTS += ["tests/mochitest.toml"]
 MOCHITEST_CHROME_MANIFESTS += ["tests/chrome/chrome.toml"]
diff --git a/netwerk/test/moz.build b/netwerk/test/moz.build
index d712354dffc9..864d1f5b87fb 100644
--- a/netwerk/test/moz.build
+++ b/netwerk/test/moz.build
@@ -27,9 +27,7 @@ TESTING_JS_MODULES += [
 
 PERFTESTS_MANIFESTS += ["perf/perftest.toml", "unit/perftest.toml"]
 
-MARIONETTE_UNIT_MANIFESTS += [
-    "marionette/manifest.toml",
-]
+MARIONETTE_MANIFESTS += ["marionette/manifest.toml"]
 
 if CONFIG["FUZZING_INTERFACES"]:
     TEST_DIRS += ["fuzz"]
diff --git a/python/mozbuild/mozbuild/frontend/context.py b/python/mozbuild/mozbuild/frontend/context.py
index 23b39120c709..551ea00feb23 100644
--- a/python/mozbuild/mozbuild/frontend/context.py
+++ b/python/mozbuild/mozbuild/frontend/context.py
@@ -2208,16 +2208,10 @@ VARIABLES = {
         """List of manifest files defining firefox-ui-functional tests.
         """,
     ),
-    "MARIONETTE_LAYOUT_MANIFESTS": (
+    "MARIONETTE_MANIFESTS": (
         ManifestparserManifestList,
         list,
-        """List of manifest files defining marionette-layout tests.
-        """,
-    ),
-    "MARIONETTE_UNIT_MANIFESTS": (
-        ManifestparserManifestList,
-        list,
-        """List of manifest files defining marionette-unit tests.
+        """List of manifest files defining marionette tests.
         """,
     ),
     "METRO_CHROME_MANIFESTS": (
diff --git a/python/mozbuild/mozbuild/testing.py b/python/mozbuild/mozbuild/testing.py
index ccbe9040b39c..c0b52cd2a06b 100644
--- a/python/mozbuild/mozbuild/testing.py
+++ b/python/mozbuild/mozbuild/testing.py
@@ -48,11 +48,7 @@ TEST_MANIFESTS = dict(
         ".",
         False,
     ),
-    # marionette tests are run from the srcdir
-    # TODO(ato): make packaging work as for other test suites
     MARIONETTE=("marionette", "marionette", ".", False),
-    MARIONETTE_UNIT=("marionette", "marionette", ".", False),
-    MARIONETTE_WEBAPI=("marionette", "marionette", ".", False),
     MOCHITEST=("mochitest", "testing/mochitest", "tests", True),
     MOCHITEST_CHROME=("chrome", "testing/mochitest", "chrome", True),
     WEBRTC_SIGNALLING_TEST=("steeplechase", "steeplechase", ".", True),
diff --git a/testing/marionette/harness/marionette_harness/tests/unit-tests.toml b/testing/marionette/harness/marionette_harness/tests/unit-tests.toml
index 836c5d25a89b..26f6f559f068 100644
--- a/testing/marionette/harness/marionette_harness/tests/unit-tests.toml
+++ b/testing/marionette/harness/marionette_harness/tests/unit-tests.toml
@@ -1,3 +1,14 @@
+# The tests within this file are exclusively executed when `mach marionette-test`
+# is called without specifying a test path. In case a specific test or manifest
+# is provided, only that particular test or manifest is executed. Alternatively,
+# by using a path prefix, any manifest file is recursively searched for under
+# the specified path.
+#
+# Note: When adding a new top-level manifest file please also add a reference
+# to the `MARIONETTE_MANIFESTS` entry in the appropriate `moz.build` file to
+# allow the execution of tests via `mach test` and as part of the test package
+# as well.
+
 [DEFAULT]
 # marionette unit tests
 ["include:unit/unit-tests.toml"]
diff --git a/testing/marionette/moz.build b/testing/marionette/moz.build
index 690b14873cf3..1986d2090424 100644
--- a/testing/marionette/moz.build
+++ b/testing/marionette/moz.build
@@ -2,7 +2,7 @@
 # License, v. 2.0. If a copy of the MPL was not distributed with this
 # file, You can obtain one at http://mozilla.org/MPL/2.0/.
 
-MARIONETTE_UNIT_MANIFESTS += ["harness/marionette_harness/tests/unit/unit-tests.toml"]
+MARIONETTE_MANIFESTS += ["harness/marionette_harness/tests/unit/unit-tests.toml"]
 
 with Files("**"):
     BUG_COMPONENT = ("Testing", "Marionette Client and Harness")
diff --git a/toolkit/components/cleardata/moz.build b/toolkit/components/cleardata/moz.build
index e3d7b3d11b4b..d3f06d8221a6 100644
--- a/toolkit/components/cleardata/moz.build
+++ b/toolkit/components/cleardata/moz.build
@@ -28,6 +28,8 @@ XPCSHELL_TESTS_MANIFESTS += ["tests/unit/xpcshell.toml"]
 
 BROWSER_CHROME_MANIFESTS += ["tests/browser/browser.toml"]
 
+MARIONETTE_MANIFESTS += ["tests/marionette/manifest.toml"]
+
 include("/ipc/chromium/chromium-config.mozbuild")
 
 with Files("**"):
diff --git a/toolkit/components/extensions/moz.build b/toolkit/components/extensions/moz.build
index 258a0108c6fd..9f22293d6de6 100644
--- a/toolkit/components/extensions/moz.build
+++ b/toolkit/components/extensions/moz.build
@@ -132,7 +132,7 @@ XPCSHELL_TESTS_MANIFESTS += [
 # in builds where they are enabled (currently only on Nightly builds).
 if CONFIG["MOZ_WEBEXT_WEBIDL_ENABLED"]:
     BROWSER_CHROME_MANIFESTS += ["test/browser/browser-serviceworker.toml"]
-    MARIONETTE_UNIT_MANIFESTS += ["test/marionette/manifest-serviceworker.toml"]
+    MARIONETTE_MANIFESTS += ["test/marionette/manifest-serviceworker.toml"]
     XPCSHELL_TESTS_MANIFESTS += [
         "test/xpcshell/webidl-api/xpcshell.toml",
         "test/xpcshell/xpcshell-serviceworker.ini",
diff --git a/toolkit/mozapps/update/moz.build b/toolkit/mozapps/update/moz.build
index 82e2c55c8407..dd9a1c1a91de 100644
--- a/toolkit/mozapps/update/moz.build
+++ b/toolkit/mozapps/update/moz.build
@@ -17,7 +17,7 @@ XPIDL_SOURCES += [
 ]
 
 TEST_DIRS += ["tests"]
-MARIONETTE_UNIT_MANIFESTS += ["tests/marionette/marionette.toml"]
+MARIONETTE_MANIFESTS += ["tests/marionette/marionette.toml"]
 
 EXTRA_COMPONENTS += [
     "nsUpdateService.manifest",
diff --git a/toolkit/xre/moz.build b/toolkit/xre/moz.build
index 07344911314b..889edbb682af 100644
--- a/toolkit/xre/moz.build
+++ b/toolkit/xre/moz.build
@@ -15,7 +15,7 @@ if CONFIG["OS_ARCH"] == "WINNT":
 MOCHITEST_MANIFESTS += ["test/mochitest.toml"]
 BROWSER_CHROME_MANIFESTS += ["test/browser.toml"]
 XPCSHELL_TESTS_MANIFESTS += ["test/xpcshell.toml"]
-MARIONETTE_UNIT_MANIFESTS += ["test/marionette/marionette.toml"]
+MARIONETTE_MANIFESTS += ["test/marionette/marionette.toml"]
 
 XPIDL_SOURCES += [
     "nsINativeAppSupport.idl",