Index: src/wp-admin/includes/theme.php
===================================================================
--- src/wp-admin/includes/theme.php	(revision 38523)
+++ src/wp-admin/includes/theme.php	(working copy)
@@ -71,6 +71,16 @@
 	$theme_dir = trailingslashit( $themes_dir . $stylesheet );
 	$deleted = $wp_filesystem->delete( $theme_dir, true );
 
+	/**
+	 * Fires immediately after a theme deletion attempt.
+	 *
+	 * @since 4.7.0
+	 *
+	 * @param string $stylesheet Stylesheet of the theme.
+	 * @param bool   $deleted    Whether the theme deletion was successful.
+	 */
+	do_action( 'deleted_theme', $stylesheet, $deleted );
+
 	if ( ! $deleted ) {
 		return new WP_Error( 'could_not_remove_theme', sprintf( __( 'Could not fully remove the theme %s.' ), $stylesheet ) );
 	}