diff --git a/README.md b/README.md
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+## [Mail System](http://drupal.org/project/mailsystem)
+
+Provides an Administrative UI and Developers API for safely updating the
+[mail_system](http://api.drupal.org/api/drupal/includes--mail.inc/function/drupal_mail_system/8)
+configuration variable.
+
+### Administrative UI
+
+The administrative interface is at `admin/config/system/mailsystem`.
+A [screenshot](http://drupal.org/node/1134044) is available.
+
+### Used by:
+
+* [HTML Mail](http://drupal.org/project/htmlmail)
+* [Mime Mail 7.x-1.x-dev](http://drupal.org/project/mimemail)
+* [Postmark 7.x-1.x](http://drupal.org/project/postmark)
+
+### Developers API
+
+A module `example` with a
+[`MailSystemInterface`](http://api.drupal.org/api/drupal/includes--mail.inc/interface/MailSystemInterface/8)
+implementation called `ExampleMailSystem` should add the following in its
+`example.install` file:
+
+    /**
+     * Implements hook_enable().
+     */
+    function example_enable() {
+      mailsystem_set(['example' => 'ExampleMailSystem']);
+    }
+
+    /**
+     * Implements hook_disable().
+     */
+    function example_disable() {
+      mailsystem_clear(['example' => 'ExampleMailSystem']);
+    }
+
+The above settings allow mail sent by `example` to use `ExampleMailSystem`.  To make
+`ExampleMailSystem` the site-wide default for sending mail:
+
+    mailsystem_set([mailsystem_default_id() => 'ExampleMailSystem']);
+
+To restore the default mail system:
+
+    mailsystem_set([mailsystem_default_id() => mailsystem_default_value()]);
+
+Or simply:
+
+    mailsystem_set(mailsystem_defaults());
+
+If module `example` relies on dependency `foo` and its `FooMailSystem` class, then
+the `example.install` code should like like this:
+
+    /**
+     * Implements hook_enable().
+     */
+    function example_enable() {
+      mailsystem_set(['example' => 'FooMailSystem']);
+    }
+
+    /**
+     * Implements hook_disable().
+     */
+    function example_disable() {
+      mailsystem_clear(['example' => '']);
+    }
+
+If module `example` only wants to use `FooMailSystem` when sending emails with a key
+of `examail`, then the `example.install` code should look like this:
+
+    /**
+     * Implements hook_enable().
+     */
+    function example_enable() {
+      mailsystem_set(['example_examail' => 'FooMailSystem']);
+    }
+
+    /**
+     * Implements hook_disable().
+     */
+    function example_disable() {
+      mailsystem_clear(['example_examail' => '']);
+    }
+
+#### *(New in 2.x branch)*
+
+To change the site-wide defaults to use the `FooMailSystem` for formatting messages and the `BarMailSystem` for sending them:
+
+    mailsystem_set(
+      [
+        mailsystem_default_id() => [
+          'format' => 'FooMailSystem',
+          'mail' => 'BarMailSystem',
+        ],
+      ]
+    );
+
+To change the site-wide defaults to use the `FooMailSystem` for sending messages, while continuing to use the current system for formatting them:
+
+    mailsystem_set(
+      [
+        mailsystem_default_id() => [
+          'mail' => 'FooMailsystem',
+        ],
+      ]
+    );
+
+### References
+
+**[`drupal_mail_system()` API documentation](http://api.drupal.org/api/drupal/includes--mail.inc/function/drupal_mail_system/8)**:
+:    [api.drupal.org/api/drupal/includes--mail.inc/function/drupal_mail_system](http://api.drupal.org/api/drupal/includes--mail.inc/function/drupal_mail_system/8)
+
+**[`MailSystemInterface` API documentation](http://api.drupal.org/api/drupal/includes--mail.inc/interface/MailSystemInterface/8)**:
+:    [api.drupal.org/api/drupal/includes--mail.inc/interface/MailSystemInterface](http://api.drupal.org/api/drupal/includes--mail.inc/interface/MailSystemInterface/8)
+
+**[Creating HTML formatted mails in Drupal 7](http://drupal.org/node/900794)**:
+:    [drupal.org/node/900794](http://drupal.org/node/900794)
+
+### References
+
+   1. <http://drupal.org/project/mailsystem>
+   2. <http://api.drupal.org/api/drupal/includes--mail.inc/function/drupal_mail_system/8>
+   3. <http://drupal.org/node/1134044>
+   4. <http://drupal.org/project/htmlmail>
+   5. <http://drupal.org/project/mimemail>
+   6. <http://drupal.org/project/postmark>
+   7. <http://api.drupal.org/api/drupal/includes--mail.inc/interface/MailSystemInterface/8>
+   8. <http://api.drupal.org/api/drupal/includes--mail.inc/function/drupal_mail_system/8>
+   9. <http://api.drupal.org/api/drupal/includes--mail.inc/function/drupal_mail_system/8>
+  10. <http://api.drupal.org/api/drupal/includes--mail.inc/interface/MailSystemInterface/8>
+  11. <http://api.drupal.org/api/drupal/includes--mail.inc/interface/MailSystemInterface/8>
+  12. <http://drupal.org/node/900794>
+  13. <http://drupal.org/node/900794>
\ No newline at end of file
diff --git a/README.txt b/README.txt
deleted file mode 100644
index fab2556..0000000
--- a/README.txt
+++ /dev/null
@@ -1,134 +0,0 @@
-[1]Mail System
-
-   Provides an Administrative UI and Developers API for safely updating
-   the [2]mail_system configuration variable.
-
-  Administrative UI
-
-   The administrative interface is at admin/config/system/mailsystem. A
-   [3]screenshot is available.
-
-  Used by:
-
-     * [4]HTML Mail
-     * [5]Mime Mail 7.x-1.x-dev
-     * [6]Postmark 7.x-1.x
-
-  Developers API
-
-   A module example with a [7]MailSystemInterface implementation called
-   ExampleMailSystem should add the following in its example.install file:
-/**
- * Implements hook_enable().
- */
-function example_enable() {
-  mailsystem_set(['example' => 'ExampleMailSystem']);
-}
-/**
- * Implements hook_disable().
- */
-function example_disable() {
-  mailsystem_clear(['example' => 'ExampleMailSystem']);
-}
-
-
-   The above settings allow mail sent by example to use ExampleMailSystem.
-   To make ExampleMailSystem the site-wide default for sending mail:
-mailsystem_set([mailsystem_default_id() => 'ExampleMailSystem']);
-
-
-   To restore the default mail system:
-mailsystem_set([mailsystem_default_id() => mailsystem_default_value()]);
-
-
-   Or simply:
-mailsystem_set(mailsystem_defaults());
-
-
-   If module example relies on dependency foo and its FooMailSystem class,
-   then the example.install code should like like this:
-/**
- * Implements hook_enable().
- */
-function example_enable() {
-  mailsystem_set(['example' => 'FooMailSystem']);
-}
-/**
- * Implements hook_disable().
- */
-function example_disable() {
-  mailsystem_clear(['example' => '']);
-}
-
-
-   If module example only wants to use FooMailSystem when sending emails
-   with a key of examail, then the example.install code should look like
-   this:
-/**
- * Implements hook_enable().
- */
-function example_enable() {
-  mailsystem_set(['example_examail' => 'FooMailSystem']);
-}
-/**
- * Implements hook_disable().
- */
-function example_disable() {
-  mailsystem_clear(['example_examail' => '']);
-}
-
-
-    (New in 2.x branch)
-
-   To change the site-wide defaults to use the FooMailSystem for
-   formatting messages and the BarMailSystem for sending them:
-mailsystem_set(
-  [
-    mailsystem_default_id() => [
-      'format' => 'FooMailSystem',
-      'mail' => 'BarMailSystem',
-    ],
-  ]
-);
-
-
-   To change the site-wide defaults to use the FooMailSystem for sending
-   messages, while continuing to use the current system for formatting
-   them:
-mailsystem_set(
-  [
-    mailsystem_default_id() => [
-      'mail' => 'FooMailsystem',
-    ],
-  ]
-);
-
-
-  References
-
-   [8]drupal_mail_system() API documentation:
-          [9]api.drupal.org/api/drupal/includes--mail.inc/function/drupal_
-          mail_system
-
-   [10]MailSystemInterface API documentation:
-          [11]api.drupal.org/api/drupal/includes--mail.inc/interface/MailS
-          ystemInterface
-
-   [12]Creating HTML formatted mails in Drupal 7:
-          [13]drupal.org/node/900794
-
-References
-
-   1. http://drupal.org/project/mailsystem
-   2. http://api.drupal.org/api/drupal/includes--mail.inc/function/drupal_mail_system/8
-   3. http://drupal.org/node/1134044
-   4. http://drupal.org/project/htmlmail
-   5. http://drupal.org/project/mimemail
-   6. http://drupal.org/project/postmark
-   7. http://api.drupal.org/api/drupal/includes--mail.inc/interface/MailSystemInterface/8
-   8. http://api.drupal.org/api/drupal/includes--mail.inc/function/drupal_mail_system/8
-   9. http://api.drupal.org/api/drupal/includes--mail.inc/function/drupal_mail_system/8
-  10. http://api.drupal.org/api/drupal/includes--mail.inc/interface/MailSystemInterface/8
-  11. http://api.drupal.org/api/drupal/includes--mail.inc/interface/MailSystemInterface/8
-  12. http://drupal.org/node/900794
-  13. http://drupal.org/node/900794
