Clarify the role of block editor context class

Author: gziolo

src/wp-includes/class-wp-block-editor-context.php

@@ -9,13 +9,18 @@
 /**
  * Class representing a current block editor context.
  *
+ * The expectation is that block editor can have a different set
+ * of requirements on every screen where it is used. This class
+ * allows to define supporting settings that can be used with filters.
+ *
  * @since 5.8.0
  */
-class WP_Block_Editor_Context {
+final class WP_Block_Editor_Context {
 	/**
 	 * Post being edited. Optional.
 	 *
 	 * @since 5.8.0
+	 *
 	 * @var WP_Post|null
 	 */
 	public $post = null;