Examples and links added

src/_includes/cache/page-cache-overview.md

@@ -21,6 +21,12 @@ We recommend using [Varnish]({{ page.baseurl }}/config-guide/varnish/config-varn
 
 To create an uncacheable page, mark any block on that page as uncacheable in the layout using `cacheable="false"`.
 
+```xml
+<block class="Magento\Customer\Block\Form\Edit" name="customer_edit" template="Magento_Customer::form/edit.phtml" cacheable="false">
+    <container name="form.additional.info" as="form_additional_info"/>
+</block>
+```
+
 Examples of uncacheable pages include the compare products, cart, [checkout](https://glossary.magento.com/checkout) pages, and so on.
 
 [Example]({{ site.mage2bloburl }}/{{ page.guide_version }}/app/code/Magento/Paypal/view/frontend/layout/paypal_payflow_returnurl.xml){:target="_blank"}

src/guides/v2.3/frontend-dev-guide/cache_for_frontdevs.md

@@ -44,7 +44,7 @@ You can clean generated static view files in any of the following ways:
 -  In the [Magento Admin](https://glossary.magento.com/magento-admin). Go to **System** > **Tools** > **Cache Management** and click **Flush [Static Files](https://glossary.magento.com/static-files) Cache**.
 
     {:.bs-callout-info}
-   This option is only available in `developer` mode. Refer to the [static view files overview]({{ page.baseurl }}/config-guide/cli/config-cli-subcommands-static-view.html#config-cli-static-overview) for more information.
+   This option is only available in `developer` mode. Refer to the [static view files overview]({{ page.baseurl }}/config-guide/cli/config-cli-subcommands-static-view.html#config-cli-static-overview) for more information. For more details about the Magento modes, see [Magento Modes]({{ page.baseurl }}/config-guide/cli/config-cli-subcommands-mode.html)
 
 -  Manually by clearing the `pub/static` and `var/view_preprocessed` directories and subdirectories _except_ for `pub/static/.htaccess`.
 

src/guides/v2.3/frontend-dev-guide/themes/product-video.md

@@ -8,7 +8,7 @@ functional_areas:
 
 ## What's in this topic
 
-In Magento 2 on product pages you can add video from external resources (currently, from [YouTube](https://youtube.com) and [Vimeo](https://vimeo.com/)). Video is [added in Admin](http://docs.magento.com/m2/2.1/ee/user_guide/catalog/product-video.html?Highlight=product%20video) when creating or editing a product.
+In Magento 2 on product pages you can add video from external resources (currently, from [YouTube](https://youtube.com) and [Vimeo](https://vimeo.com/)). Video is [added in Admin](https://docs.magento.com/user-guide/catalog/product-video.html) when creating or editing a product.
 Certain product video options can be set in the `config.xml` configuration file. These settings are not theme-specific.
 
 ## Configure product video options

src/guides/v2.3/frontend-dev-guide/themes/theme-create.md

@@ -22,7 +22,7 @@ The high-level steps required to add a new theme in the Magento system are the f
 
 1. Create a directory for the theme under `app/design/frontend/<your_vendor_name>/<your_theme_name>`.
 1. Add a declaration file `theme.xml` and optionally create `etc` directory and create a file named `view.xml` to the theme directory.
-1. Add a `composer.json` file.
+1. Add a `composer.json` file (Optional).
 1. Add `registration.php`.
 1. Create directories for CSS, JavaScript, images, and fonts.
 1. Configure your theme in the [Admin](https://glossary.magento.com/admin) panel.
@@ -70,6 +70,8 @@ After you create a directory for your theme, you must create `theme.xml` contain
    </theme>
    ```
 
+   Add the `preview.jpg` file to the `app/design/frontend/<Vendor>/<theme>/media/` directory.
+
    If you do not have a preview image for your theme, remove the `<media>` node:
 
    ```xml