diff --git a/scripts/gulpfiles/build_tasks.js b/scripts/gulpfiles/build_tasks.js
index b2abe9f98..aa7b77f39 100644
--- a/scripts/gulpfiles/build_tasks.js
+++ b/scripts/gulpfiles/build_tasks.js
@@ -66,7 +66,25 @@ const NAMESPACE_OBJECT = '$';
 /**
  * A list of chunks.  Order matters: later chunks can depend on
  * earlier ones, but not vice-versa.  All chunks are assumed to depend
- * on the first chunk.
+ * on the first chunk.  Properties are as follows:
+ *
+ * - .name: the name of the chunk.  Used to label it when describing
+ *   it to Closure Compiler and forms the prefix of filename the chunk
+ *   will be written to.
+ * - .entry: the source .js file which is the entrypoint for the
+ *   chunk.
+ * - .exports: a variable or property that will (prefixed with
+ *   NAMESPACE_OBJECT) be returned from the factory function and which
+ *   (sans prefix) will be set in the global scope to that returned
+ *   value if the module is loaded in a browser.
+ * - .importAs: the name that this chunk's exports object will be
+ *   given when passed to the factory function of other chunks that
+ *   depend on it.  (Needs to be distinct from .exports since (e.g.)
+ *   "Blockly.blocks.all" is not a valid variable name.)
+ * - .factoryPreamble: code to override the default wrapper factory
+ *   function preamble.
+ * - .factoryPostamble: code to override the default wrapper factory
+ *   function postabmle.
  *
  * The function getChunkOptions will, after running
  * closure-calculate-chunks, update each chunk to add the following
@@ -81,37 +99,49 @@ const chunks = [
   {
     name: 'blockly',
     entry: 'core/requires.js',
-    namespace: 'Blockly',
-    wrapperSetup: `const ${NAMESPACE_OBJECT}={};`,
-    wrapperCleanup:
+    exports: 'Blockly',
+    importAs: 'Blockly',
+    factoryPreamble: `const ${NAMESPACE_OBJECT}={};`,
+    factoryPostamble:
         `${NAMESPACE_OBJECT}.Blockly.internal_=${NAMESPACE_OBJECT};`,
   }, {
     name: 'blocks',
     entry: 'blocks/all.js',
-    namespace: 'Blockly.blocks',
+    exports: 'Blockly.Blocks',
+    importAs: 'BlocklyBlocks',
   }, {
     name: 'javascript',
     entry: 'generators/javascript/all.js',
-    namespace: 'Blockly.JavaScript',
+    exports: 'Blockly.JavaScript',
   }, {
     name: 'python',
     entry: 'generators/python/all.js',
-    namespace: 'Blockly.Python',
+    exports: 'Blockly.Python',
   }, {
     name: 'php',
     entry: 'generators/php/all.js',
-    namespace: 'Blockly.PHP',
+    exports: 'Blockly.PHP',
   }, {
     name: 'lua',
     entry: 'generators/lua/all.js',
-    namespace: 'Blockly.Lua',
+    exports: 'Blockly.Lua',
   }, {
     name: 'dart',
     entry: 'generators/dart/all.js',
-    namespace: 'Blockly.Dart',
+    exports: 'Blockly.Dart',
   }
 ];
 
+/**
+ * The default factory function premable.
+ */
+const FACTORY_PREAMBLE = `const ${NAMESPACE_OBJECT}=Blockly.internal_;`;
+
+/**
+ * The default factory function postamble.
+ */
+const FACTORY_POSTAMBLE = '';
+
 const licenseRegex = `\\/\\*\\*
  \\* @license
  \\* (Copyright \\d+ (Google LLC|Massachusetts Institute of Technology))
@@ -283,8 +313,8 @@ function chunkWrapper(chunk) {
   const amdDeps = fileNames.join(', ');
   const cjsDeps = fileNames.map(f => `require(${f})`).join(', ');
   const browserDeps =
-      chunk.dependencies.map(d => `root.${d.namespace}`).join(', ');
-  const imports = chunk.dependencies.map(d => d.namespace).join(', ');
+      chunk.dependencies.map(d => `root.${d.exports}`).join(', ');
+  const imports = chunk.dependencies.map(d => d.importAs).join(', ');
   return `// Do not edit this file; automatically generated.
 
 /* eslint-disable */
@@ -294,13 +324,13 @@ function chunkWrapper(chunk) {
   } else if (typeof exports === 'object') { // Node.js
     module.exports = factory(${cjsDeps});
   } else { // Browser
-    root.${chunk.namespace} = factory(${browserDeps});
+    root.${chunk.exports} = factory(${browserDeps});
   }
 }(this, function(${imports}) {
-${chunk.wrapperSetup || `const ${NAMESPACE_OBJECT}=Blockly.internal_;`}
+${chunk.factoryPreamble || FACTORY_PREAMBLE}
 %output%
-${chunk.wrapperCleanup || ''}
-return ${NAMESPACE_OBJECT}.${chunk.namespace};
+${chunk.factoryPostamble || FACTORY_POSTAMBLE}
+return ${NAMESPACE_OBJECT}.${chunk.exports};
 }));
 `;
 };
diff --git a/scripts/gulpfiles/package_tasks.js b/scripts/gulpfiles/package_tasks.js
index fefb2d9f8..9d7edca04 100644
--- a/scripts/gulpfiles/package_tasks.js
+++ b/scripts/gulpfiles/package_tasks.js
@@ -126,8 +126,8 @@ function packageBlockly() {
  */
 function packageBlocks() {
   return gulp.src('scripts/package/blocks.js')
-    .pipe(packageUMD('Blockly.Blocks', [{
-        name: 'Blockly',
+    .pipe(packageUMD('BlocklyBlocks', [{
+        name: 'BlocklyBlocks',
         amd: './blocks_compressed',
         cjs: './blocks_compressed',
       }]))
diff --git a/scripts/package/blockly.js b/scripts/package/blockly.js
index 55bc791af..77021b3d6 100644
--- a/scripts/package/blockly.js
+++ b/scripts/package/blockly.js
@@ -5,8 +5,5 @@
  */
 
 /**
- * @fileoverview Blockly module.
+ * @fileoverview Blockly module; just a wrapper for blockly_compressed.js.
  */
-
-/* eslint-disable */
-'use strict';
diff --git a/scripts/package/blocks.js b/scripts/package/blocks.js
index 8e0d4ab79..66ae806bf 100644
--- a/scripts/package/blocks.js
+++ b/scripts/package/blocks.js
@@ -5,10 +5,5 @@
  */
 
 /**
- * @fileoverview Blockly Blocks module.
+ * @fileoverview Blockly blocks module; just a wrapper for blocks_compressed.js.
  */
-
-/* eslint-disable */
-'use strict';
-
-Blockly.Blocks = {};
diff --git a/scripts/package/browser/core.js b/scripts/package/browser/core.js
index 19463cd7e..a0b0d9259 100644
--- a/scripts/package/browser/core.js
+++ b/scripts/package/browser/core.js
@@ -14,7 +14,6 @@
 
 // Add a helper method to set the Blockly locale.
 Blockly.setLocale = function (locale) {
-  Blockly.Msg = Blockly.Msg || {};
   Object.keys(locale).forEach(function (k) {
     Blockly.Msg[k] = locale[k];
   });
diff --git a/scripts/package/browser/index.js b/scripts/package/browser/index.js
index 1b2f05e51..36d0c325b 100644
--- a/scripts/package/browser/index.js
+++ b/scripts/package/browser/index.js
@@ -15,10 +15,3 @@
 
 // Include the EN Locale by default.
 Blockly.setLocale(En);
-
-Blockly.Blocks = Blockly.Blocks || {};
-Object.keys(BlocklyBlocks).forEach(function (k) {
-  Blockly.Blocks[k] = BlocklyBlocks[k];
-});
-
-Blockly.JavaScript = BlocklyJS;
\ No newline at end of file
diff --git a/scripts/package/dart.js b/scripts/package/dart.js
index ea4e8338a..d59060bde 100644
--- a/scripts/package/dart.js
+++ b/scripts/package/dart.js
@@ -5,10 +5,5 @@
  */
 
 /**
- * @fileoverview Dart Generator module.
+ * @fileoverview Dart generator module; just a wrapper for dart_compressed.js.
  */
-
-/* eslint-disable */
-'use strict';
-
-Blockly.Dart = BlocklyDart;
diff --git a/scripts/package/index.js b/scripts/package/index.js
index f88c16e73..0264fd446 100644
--- a/scripts/package/index.js
+++ b/scripts/package/index.js
@@ -5,8 +5,7 @@
  */
 
 /**
- * @fileoverview Blockly module.
+ * @fileoverview Blockly module; this is a wrapper which selects
+ *     either browser.js or node.js, depending on which environment we
+ *     are running in.
  */
-
-/* eslint-disable */
-'use strict';
\ No newline at end of file
diff --git a/scripts/package/javascript.js b/scripts/package/javascript.js
index e0ba813f2..e4adba09f 100644
--- a/scripts/package/javascript.js
+++ b/scripts/package/javascript.js
@@ -5,10 +5,6 @@
  */
 
 /**
- * @fileoverview JavaScript Generator module.
+ * @fileoverview JavaScript Generator module; just a wrapper for
+ *     javascript_compressed.js.
  */
-
-/* eslint-disable */
-'use strict';
-
-Blockly.JavaScript = BlocklyJavaScript;
diff --git a/scripts/package/lua.js b/scripts/package/lua.js
index 4094782a1..ca37b44f9 100644
--- a/scripts/package/lua.js
+++ b/scripts/package/lua.js
@@ -5,10 +5,5 @@
  */
 
 /**
- * @fileoverview Lua Generator module.
+ * @fileoverview Lua generator module; just a wrapper for lua_compressed.js.
  */
-
-/* eslint-disable */
-'use strict';
-
-Blockly.Lua = BlocklyLua;
diff --git a/scripts/package/node/core.js b/scripts/package/node/core.js
index 9692855d3..36a5addd2 100644
--- a/scripts/package/node/core.js
+++ b/scripts/package/node/core.js
@@ -14,7 +14,6 @@
 
 // Add a helper method to set the Blockly locale.
 Blockly.setLocale = function (locale) {
-  Blockly.Msg = Blockly.Msg || {};
   Object.keys(locale).forEach(function (k) {
     Blockly.Msg[k] = locale[k];
   });
diff --git a/scripts/package/node/index.js b/scripts/package/node/index.js
index d50a92d60..33c322a98 100644
--- a/scripts/package/node/index.js
+++ b/scripts/package/node/index.js
@@ -14,18 +14,3 @@
 
 // Include the EN Locale by default.
 Blockly.setLocale(En);
-
-Blockly.Blocks = Blockly.Blocks || {};
-Object.keys(BlocklyBlocks).forEach(function (k) {
-  Blockly.Blocks[k] = BlocklyBlocks[k];
-});
-
-Blockly.JavaScript = BlocklyJS;
-
-Blockly.Python = BlocklyPython;
-
-Blockly.Lua = BlocklyLua;
-
-Blockly.PHP = BlocklyPHP;
-
-Blockly.Dart = BlocklyDart;
\ No newline at end of file
diff --git a/scripts/package/php.js b/scripts/package/php.js
index 361dd97ec..a6ed3fa6d 100644
--- a/scripts/package/php.js
+++ b/scripts/package/php.js
@@ -5,10 +5,5 @@
  */
 
 /**
- * @fileoverview PHP Generator module.
+ * @fileoverview PHP generator module; just a wrapper for php_compressed.js.
  */
-
-/* eslint-disable */
-'use strict';
-
-Blockly.PHP = BlocklyPHP;
diff --git a/scripts/package/python.js b/scripts/package/python.js
index 3634e41bf..0bb64c06f 100644
--- a/scripts/package/python.js
+++ b/scripts/package/python.js
@@ -5,10 +5,6 @@
  */
 
 /**
- * @fileoverview Python Generator module.
+ * @fileoverview Python generator module; just a wrapper for
+ *     python_compressed.js.
  */
-
-/* eslint-disable */
-'use strict';
-
-Blockly.Python = BlocklyPython;