Index: src/wp-includes/user.php
===================================================================
--- src/wp-includes/user.php	(revision 43328)
+++ src/wp-includes/user.php	(working copy)
@@ -3088,10 +3088,11 @@
 		return;
 	}

-	$subject = sprintf(
+	$blogname = wp_specialchars_decode( get_option( 'blogname' ), ENT_QUOTES );
+	$subject  = sprintf(
 		/* translators: %s Site name. */
 		__( '[%s] Erasure Request Fulfilled' ),
-		wp_specialchars_decode( get_option( 'blogname' ), ENT_QUOTES )
+		$blogname
 	);

 	/**
@@ -3171,6 +3172,27 @@
 	 */
 	$content = apply_filters( 'user_confirmed_action_email_content', $email_text, $email_data );

+	/**
+	 * Filters the subject of the email sent when an erasure request is completed.
+	 *
+	 * @since 4.9.7
+	 *
+	 * @param string $subject    The email subject.
+	 * @param string $blogname   The name of the site.
+	 * @param array  $email_data {
+	 *     Data relating to the account action email.
+	 *
+	 *     @type WP_User_Request $request            User request object.
+	 *     @type string          $message_recipient  The address that the email will be sent to. Defaults
+	 *                                               to the value of `$request->email`, but can be changed
+	 *                                               by the `user_erasure_fulfillment_email_to` filter.
+	 *     @type string          $privacy_policy_url Privacy policy URL.
+	 *     @type string          $sitename           The site name sending the mail.
+	 *     @type string          $siteurl            The site URL sending the mail.
+	 * }
+	 */
+	$subject = apply_filters( 'user_erasure_complete_email_subject', $subject, $blogname, $email_data );
+
 	$content = str_replace( '###SITENAME###', wp_specialchars_decode( $email_data['sitename'], ENT_QUOTES ), $content );
 	$content = str_replace( '###PRIVACY_POLICY_URL###', $email_data['privacy_policy_url'], $content );
 	$content = str_replace( '###SITEURL###', esc_url_raw( $email_data['siteurl'] ), $content );