ENGCOM-9329: Update Catalog Module README Content #34423

Author: sidolov

app/code/Magento/Catalog/README.md

@@ -1,6 +1,72 @@
+#Magento_Catalog
 Magento_Catalog module functionality is represented by the following sub-systems:
  - Products Management. It includes CRUD operation of product, product media, product attributes, etc...
  - Category Management. It includes CRUD operation of category, category attributes
 
 Catalog module provides mechanism for creating new product type in the system.
 Catalog module provides API filtering that allows to limit product selection with advanced filters.
+
+## Structure
+
+  [Learn about a typical file structure for a Magento 2 module]
+  (https://devdocs.magento.com/guides/v2.4/extension-dev-guide/build/module-file-structure.html).
+
+## Observer
+This module observes the following events:
+   `etc/events.xml`
+	   `magento_catalog_api_data_productinterface_save_before` event in
+	   `Magento\Framework\EntityManager\Observer\BeforeEntitySave` file.
+	   `magento_catalog_api_data_productinterface_save_after` event in
+	   `Magento\Framework\EntityManager\Observer\AfterEntitySave` file.
+	   `magento_catalog_api_data_productinterface_delete_before` event in
+	   `Magento\Framework\EntityManager\Observer\BeforeEntityDelete` file.
+	   `magento_catalog_api_data_productinterface_delete_after` event in
+	   `Magento\Framework\EntityManager\Observer\AfterEntityDelete` file.
+	   `magento_catalog_api_data_productinterface_load_after` event in
+	   `Magento\Framework\EntityManager\Observer\AfterEntityLoad` file.
+	   `magento_catalog_api_data_categoryinterface_save_before` event in
+	   `Magento\Framework\EntityManager\Observer\BeforeEntitySave` file.
+	   `magento_catalog_api_data_categoryinterface_save_after` event in
+	   `Magento\Framework\EntityManager\Observer\AfterEntitySave` file.
+	   `magento_catalog_api_data_categoryinterface_save_after` event in
+	   `Magento\Catalog\Observer\InvalidateCacheOnCategoryDesignChange` file.
+	   `magento_catalog_api_data_categoryinterface_delete_before` event in
+	   `Magento\Framework\EntityManager\Observer\BeforeEntityDelete` file.
+	   `magento_catalog_api_data_categoryinterface_delete_after` event in
+	   `Magento\Framework\EntityManager\Observer\AfterEntityDelete` file.
+	   `magento_catalog_api_data_categoryinterface_load_after` event in
+	   `Magento\Framework\EntityManager\Observer\AfterEntityLoad` file.
+	   `magento_catalog_api_data_categorytreeinterface_save_before` event in
+	   `Magento\Framework\EntityManager\Observer\BeforeEntitySave` file.
+	   `magento_catalog_api_data_categorytreeinterface_save_after` event in
+	   `Magento\Framework\EntityManager\Observer\AfterEntitySave` file.
+	   `magento_catalog_api_data_categorytreeinterface_delete_before` event in
+	   `Magento\Framework\EntityManager\Observer\BeforeEntityDelete` file.
+	   `magento_catalog_api_data_categorytreeinterface_delete_after` event in
+	   `Magento\Framework\EntityManager\Observer\AfterEntityDelete` file.
+	   `magento_catalog_api_data_categorytreeinterface_load_after` event in
+	   `Magento\Framework\EntityManager\Observer\AfterEntityLoad` file.
+	   `admin_system_config_changed_section_catalog` event in
+	   `Magento\Catalog\Observer\SwitchPriceAttributeScopeOnConfigChange` file.
+	   `catalog_product_save_before` event in
+	   `Magento\Catalog\Observer\SetSpecialPriceStartDate` file.
+	   `store_save_after` event in
+	   `Magento\Catalog\Observer\SynchronizeWebsiteAttributesOnStoreChange` file.
+	   `catalog_product_save_commit_after` event in
+	   `Magento\Catalog\Observer\ImageResizeAfterProductSave` file.
+	   `catalog_category_prepare_save` event in
+	   `Magento\Catalog\Observer\CategoryDesignAuthorization` file.
+   
+    `/etc/frontend/events.xml`
+	   `customer_login` event in
+	   `Magento\Catalog\Observer\Compare\BindCustomerLoginObserver` file.
+		`customer_logout` event in
+	   `Magento\Catalog\Observer\Compare\BindCustomerLogoutObserver` file.
+   
+    `/etc/adminhtml/events.xml`
+		`cms_wysiwyg_images_static_urls_allowed` event in
+	   `Magento\Catalog\Observer\CatalogCheckIsUsingStaticUrlsAllowedObserver` file.
+		`catalog_category_change_products` event in
+	   `Magento\Catalog\Observer\CategoryProductIndexer` file.
+		`category_move` event in
+	   `Magento\Catalog\Observer\FlushCategoryPagesCache`