diff --git a/packages/docusaurus-1.x/examples/basics/static/css/custom.css b/packages/docusaurus-1.x/examples/basics/static/css/custom.css
index 220c1dde7d..01aa4ed36d 100644
--- a/packages/docusaurus-1.x/examples/basics/static/css/custom.css
+++ b/packages/docusaurus-1.x/examples/basics/static/css/custom.css
@@ -1,3 +1,10 @@
+/**
+ * Copyright (c) 2017-present, Facebook, Inc.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+ 
 /* your custom css */
 
 @media only screen and (min-device-width: 360px) and (max-device-width: 736px) {
diff --git a/packages/docusaurus-mdx-loader/src/remark/rightToc/__tests__/fixtures/empty-headings.mdx b/packages/docusaurus-mdx-loader/src/remark/rightToc/__tests__/fixtures/empty-headings.md
similarity index 100%
rename from packages/docusaurus-mdx-loader/src/remark/rightToc/__tests__/fixtures/empty-headings.mdx
rename to packages/docusaurus-mdx-loader/src/remark/rightToc/__tests__/fixtures/empty-headings.md
diff --git a/packages/docusaurus-mdx-loader/src/remark/rightToc/__tests__/fixtures/insert-below-imports.mdx b/packages/docusaurus-mdx-loader/src/remark/rightToc/__tests__/fixtures/insert-below-imports.md
similarity index 100%
rename from packages/docusaurus-mdx-loader/src/remark/rightToc/__tests__/fixtures/insert-below-imports.mdx
rename to packages/docusaurus-mdx-loader/src/remark/rightToc/__tests__/fixtures/insert-below-imports.md
diff --git a/packages/docusaurus-mdx-loader/src/remark/rightToc/__tests__/fixtures/just-content.mdx b/packages/docusaurus-mdx-loader/src/remark/rightToc/__tests__/fixtures/just-content.md
similarity index 100%
rename from packages/docusaurus-mdx-loader/src/remark/rightToc/__tests__/fixtures/just-content.mdx
rename to packages/docusaurus-mdx-loader/src/remark/rightToc/__tests__/fixtures/just-content.md
diff --git a/packages/docusaurus-mdx-loader/src/remark/rightToc/__tests__/fixtures/name-exist.mdx b/packages/docusaurus-mdx-loader/src/remark/rightToc/__tests__/fixtures/name-exist.md
similarity index 100%
rename from packages/docusaurus-mdx-loader/src/remark/rightToc/__tests__/fixtures/name-exist.mdx
rename to packages/docusaurus-mdx-loader/src/remark/rightToc/__tests__/fixtures/name-exist.md
diff --git a/packages/docusaurus-mdx-loader/src/remark/rightToc/__tests__/fixtures/non-text-content.mdx b/packages/docusaurus-mdx-loader/src/remark/rightToc/__tests__/fixtures/non-text-content.md
similarity index 100%
rename from packages/docusaurus-mdx-loader/src/remark/rightToc/__tests__/fixtures/non-text-content.mdx
rename to packages/docusaurus-mdx-loader/src/remark/rightToc/__tests__/fixtures/non-text-content.md
diff --git a/packages/docusaurus-mdx-loader/src/remark/rightToc/__tests__/index.test.js b/packages/docusaurus-mdx-loader/src/remark/rightToc/__tests__/index.test.js
index 9b694d2d86..9535ad1564 100644
--- a/packages/docusaurus-mdx-loader/src/remark/rightToc/__tests__/index.test.js
+++ b/packages/docusaurus-mdx-loader/src/remark/rightToc/__tests__/index.test.js
@@ -12,7 +12,7 @@ import vfile from 'to-vfile';
 import plugin from '../index';
 
 const processFixture = async (name, options) => {
-  const path = join(__dirname, 'fixtures', `${name}.mdx`);
+  const path = join(__dirname, 'fixtures', `${name}.md`);
   const file = await vfile.read(path);
   const result = await remark()
     .use(mdx)
diff --git a/packages/docusaurus-plugin-content-blog/src/__tests__/generateBlogFeed.test.ts b/packages/docusaurus-plugin-content-blog/src/__tests__/generateBlogFeed.test.ts
index a0eea6ca6f..7f76e9c4d2 100644
--- a/packages/docusaurus-plugin-content-blog/src/__tests__/generateBlogFeed.test.ts
+++ b/packages/docusaurus-plugin-content-blog/src/__tests__/generateBlogFeed.test.ts
@@ -1,3 +1,10 @@
+/**
+ * Copyright (c) 2017-present, Facebook, Inc.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
 import path from 'path';
 import {generateBlogFeed} from '../blogUtils';
 import {LoadContext} from '@docusaurus/types';
diff --git a/packages/docusaurus-plugin-content-blog/src/types.ts b/packages/docusaurus-plugin-content-blog/src/types.ts
index dfea976e33..40852673e7 100644
--- a/packages/docusaurus-plugin-content-blog/src/types.ts
+++ b/packages/docusaurus-plugin-content-blog/src/types.ts
@@ -1,3 +1,10 @@
+/**
+ * Copyright (c) 2017-present, Facebook, Inc.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
 export interface BlogContent {
   blogPosts: BlogPost[];
   blogListPaginated: BlogPaginated[];
diff --git a/packages/docusaurus-plugin-content-docs/src/__tests__/__fixtures__/sidebars/sidebars-first-level-not-category.js b/packages/docusaurus-plugin-content-docs/src/__tests__/__fixtures__/sidebars/sidebars-first-level-not-category.js
index 17b0f9bb7d..551a377c70 100644
--- a/packages/docusaurus-plugin-content-docs/src/__tests__/__fixtures__/sidebars/sidebars-first-level-not-category.js
+++ b/packages/docusaurus-plugin-content-docs/src/__tests__/__fixtures__/sidebars/sidebars-first-level-not-category.js
@@ -1,3 +1,10 @@
+/**
+ * Copyright (c) 2017-present, Facebook, Inc.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
 module.exports = {
   docs: [
     {
diff --git a/packages/docusaurus-theme-classic/src/theme/CodeBlock/styles.module.css b/packages/docusaurus-theme-classic/src/theme/CodeBlock/styles.module.css
index f935f6dc76..fe4c9a644d 100644
--- a/packages/docusaurus-theme-classic/src/theme/CodeBlock/styles.module.css
+++ b/packages/docusaurus-theme-classic/src/theme/CodeBlock/styles.module.css
@@ -1,3 +1,10 @@
+/**
+ * Copyright (c) 2017-present, Facebook, Inc.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
 .codeBlockWrapper {
   position: relative;
 }
diff --git a/packages/docusaurus-theme-classic/src/theme/MDXComponents/styles.module.css b/packages/docusaurus-theme-classic/src/theme/MDXComponents/styles.module.css
index 7e40658401..7f782bbb31 100644
--- a/packages/docusaurus-theme-classic/src/theme/MDXComponents/styles.module.css
+++ b/packages/docusaurus-theme-classic/src/theme/MDXComponents/styles.module.css
@@ -1,3 +1,10 @@
+/**
+ * Copyright (c) 2017-present, Facebook, Inc.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
 .mdxCodeBlock {
   background-color: transparent;
   border-radius: var(--ifm-global-radius);
diff --git a/packages/docusaurus-types/src/index.d.ts b/packages/docusaurus-types/src/index.d.ts
index 19906268dd..f26c3add89 100644
--- a/packages/docusaurus-types/src/index.d.ts
+++ b/packages/docusaurus-types/src/index.d.ts
@@ -1,3 +1,10 @@
+/**
+ * Copyright (c) 2017-present, Facebook, Inc.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
 import {Loader, Configuration} from 'webpack';
 import {Command} from 'commander';
 import {ParsedUrlQueryInput} from 'querystring';
diff --git a/packages/docusaurus/src/server/client-modules/__tests__/__fixtures__/plugin-empty.js b/packages/docusaurus/src/server/client-modules/__tests__/__fixtures__/plugin-empty.js
index 8c0267bc46..8217b22cd2 100644
--- a/packages/docusaurus/src/server/client-modules/__tests__/__fixtures__/plugin-empty.js
+++ b/packages/docusaurus/src/server/client-modules/__tests__/__fixtures__/plugin-empty.js
@@ -1,3 +1,10 @@
+/**
+ * Copyright (c) 2017-present, Facebook, Inc.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
 module.exports = function() {
   return {
     name: 'plugin-empty',
diff --git a/packages/docusaurus/src/server/client-modules/__tests__/__fixtures__/plugin-foo-bar.js b/packages/docusaurus/src/server/client-modules/__tests__/__fixtures__/plugin-foo-bar.js
index 13f86d13b3..ef0bf04e2b 100644
--- a/packages/docusaurus/src/server/client-modules/__tests__/__fixtures__/plugin-foo-bar.js
+++ b/packages/docusaurus/src/server/client-modules/__tests__/__fixtures__/plugin-foo-bar.js
@@ -1,3 +1,10 @@
+/**
+ * Copyright (c) 2017-present, Facebook, Inc.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
 module.exports = function() {
   return {
     name: 'plugin-foo-bar',
diff --git a/packages/docusaurus/src/server/client-modules/__tests__/__fixtures__/plugin-hello-world.js b/packages/docusaurus/src/server/client-modules/__tests__/__fixtures__/plugin-hello-world.js
index 72fb606391..f8ff2aaccd 100644
--- a/packages/docusaurus/src/server/client-modules/__tests__/__fixtures__/plugin-hello-world.js
+++ b/packages/docusaurus/src/server/client-modules/__tests__/__fixtures__/plugin-hello-world.js
@@ -1,3 +1,10 @@
+/**
+ * Copyright (c) 2017-present, Facebook, Inc.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
 module.exports = function() {
   return {
     plugin: 'plugin-hello-world',
diff --git a/packages/docusaurus/src/server/presets/__tests__/__fixtures__/preset-bar.js b/packages/docusaurus/src/server/presets/__tests__/__fixtures__/preset-bar.js
index b9b8527505..91c3d1aeba 100644
--- a/packages/docusaurus/src/server/presets/__tests__/__fixtures__/preset-bar.js
+++ b/packages/docusaurus/src/server/presets/__tests__/__fixtures__/preset-bar.js
@@ -1,3 +1,10 @@
+/**
+ * Copyright (c) 2017-present, Facebook, Inc.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
 module.exports = function preset(context, opts = {}) {
   return {
     plugins: [
diff --git a/packages/docusaurus/src/server/presets/__tests__/__fixtures__/preset-foo.js b/packages/docusaurus/src/server/presets/__tests__/__fixtures__/preset-foo.js
index 9475a381f3..c3d4f909b3 100644
--- a/packages/docusaurus/src/server/presets/__tests__/__fixtures__/preset-foo.js
+++ b/packages/docusaurus/src/server/presets/__tests__/__fixtures__/preset-foo.js
@@ -1,3 +1,10 @@
+/**
+ * Copyright (c) 2017-present, Facebook, Inc.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
 module.exports = function preset(context, opts = {}) {
   return {
     plugins: [
diff --git a/packages/docusaurus/src/server/presets/__tests__/__fixtures__/preset-qux.js b/packages/docusaurus/src/server/presets/__tests__/__fixtures__/preset-qux.js
index 273776f0ed..6e0b6088df 100644
--- a/packages/docusaurus/src/server/presets/__tests__/__fixtures__/preset-qux.js
+++ b/packages/docusaurus/src/server/presets/__tests__/__fixtures__/preset-qux.js
@@ -1,3 +1,10 @@
+/**
+ * Copyright (c) 2017-present, Facebook, Inc.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
 module.exports = function preset(context, opts = {}) {
   return {
     themes: [['@docusaurus/theme-classic', opts.test]],
diff --git a/packages/docusaurus/src/server/themes/__tests__/__fixtures__/theme-1/Footer/index.js b/packages/docusaurus/src/server/themes/__tests__/__fixtures__/theme-1/Footer/index.js
index 461f67a0a4..5ab81b41d6 100644
--- a/packages/docusaurus/src/server/themes/__tests__/__fixtures__/theme-1/Footer/index.js
+++ b/packages/docusaurus/src/server/themes/__tests__/__fixtures__/theme-1/Footer/index.js
@@ -1 +1,8 @@
+/**
+ * Copyright (c) 2017-present, Facebook, Inc.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
 export default () => null;
diff --git a/packages/docusaurus/src/server/themes/__tests__/__fixtures__/theme-1/Layout.js b/packages/docusaurus/src/server/themes/__tests__/__fixtures__/theme-1/Layout.js
index 461f67a0a4..5ab81b41d6 100644
--- a/packages/docusaurus/src/server/themes/__tests__/__fixtures__/theme-1/Layout.js
+++ b/packages/docusaurus/src/server/themes/__tests__/__fixtures__/theme-1/Layout.js
@@ -1 +1,8 @@
+/**
+ * Copyright (c) 2017-present, Facebook, Inc.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
 export default () => null;
diff --git a/packages/docusaurus/src/server/themes/__tests__/__fixtures__/theme-2/Layout/index.js b/packages/docusaurus/src/server/themes/__tests__/__fixtures__/theme-2/Layout/index.js
index 461f67a0a4..5ab81b41d6 100644
--- a/packages/docusaurus/src/server/themes/__tests__/__fixtures__/theme-2/Layout/index.js
+++ b/packages/docusaurus/src/server/themes/__tests__/__fixtures__/theme-2/Layout/index.js
@@ -1 +1,8 @@
+/**
+ * Copyright (c) 2017-present, Facebook, Inc.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
 export default () => null;
diff --git a/packages/docusaurus/src/server/themes/__tests__/__fixtures__/theme-2/Navbar.js b/packages/docusaurus/src/server/themes/__tests__/__fixtures__/theme-2/Navbar.js
index 461f67a0a4..5ab81b41d6 100644
--- a/packages/docusaurus/src/server/themes/__tests__/__fixtures__/theme-2/Navbar.js
+++ b/packages/docusaurus/src/server/themes/__tests__/__fixtures__/theme-2/Navbar.js
@@ -1 +1,8 @@
+/**
+ * Copyright (c) 2017-present, Facebook, Inc.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
 export default () => null;
diff --git a/website/src/components/BrowserWindow/styles.module.css b/website/src/components/BrowserWindow/styles.module.css
index 020bc6c7e4..d1b4d7c413 100644
--- a/website/src/components/BrowserWindow/styles.module.css
+++ b/website/src/components/BrowserWindow/styles.module.css
@@ -1,3 +1,10 @@
+/**
+ * Copyright (c) 2017-present, Facebook, Inc.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+ 
 .browserWindow {
   border: 3px solid var(--ifm-color-emphasis-200);
   border-top-left-radius: var(--ifm-global-radius);