new file mode 100644
--- /dev/null
+++ b/build/data.py
@@ -0,0 +1,21 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# 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/.
+
+# This file contains shared, read-only build data. Common lists of things,
+# etc.
+
+from __future__ import absolute_import, unicode_literals
+
+from mozbuild.util import (
+    ReadOnlyDict,
+)
+
+
+DATA = {
+
+}
+
+# TODO Ideally we'd iterate members and make them read-only as well.
+# For now, rely on people not doing stupid things.
+DATA = ReadOnlyDict(DATA)

--- a/python/mozbuild/mozbuild/backend/configenvironment.py
+++ b/python/mozbuild/mozbuild/backend/configenvironment.py
@@ -1,16 +1,18 @@
 # This Source Code Form is subject to the terms of the Mozilla Public
 # 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/.
 
 from __future__ import absolute_import
 
+import imp
 import os
 import sys
+import uuid
 
 from collections import Iterable
 from types import StringTypes
 
 import mozpack.path as mozpath
 
 from mozbuild.util import ReadOnlyDict
 from mozbuild.shellutil import quote as shell_quote
@@ -174,16 +176,23 @@ class ConfigEnvironment(object):
                     type(v)(decode(i) for i in v)
             elif not isinstance(v, text_type):
                 v = decode(v)
 
             self.substs_unicode[k] = v
 
         self.substs_unicode = ReadOnlyDict(self.substs_unicode)
 
+        # Load data module containing static data.
+        data_path = os.path.join(self.topsrcdir, 'build', 'data.py')
+        # Randomize module name to prevent conflicts.
+        data_mod = imp.load_source('mozbuild.build_data_%s' % uuid.uuid4(),
+                                   data_path)
+        self.data = data_mod.DATA
+
     @property
     def is_artifact_build(self):
         return self.substs.get('MOZ_ARTIFACT_BUILDS', False)
 
     @staticmethod
     def from_config_status(path):
         config = BuildConfig.from_config_status(path)