Use site host in backup codes download title

providers/class-two-factor-backup-codes.php

@@ -358,9 +358,19 @@ public function rest_generate_codes( $request ) {
 		$title = sprintf(
 			/* translators: %s: the site's domain */
 			__( 'Two-Factor Recovery Codes for %s', 'two-factor' ),
-			home_url( '/' )
+			wp_parse_url( home_url(), PHP_URL_HOST )
 		);
 
+		/**
+		 * Filters the title in the backup codes download file.
+		 *
+		 * @since 0.17.0
+		 *
+		 * @param string  $title Title for the backup codes download file.
+		 * @param WP_User $user  User for whom the backup codes were generated.
+		 */
+		$title = apply_filters( 'two_factor_backup_codes_download_title', $title, $user );
+
 		// Generate download content.
 		$download_link  = 'data:application/text;charset=utf-8,';
 		$download_link .= rawurlencode( "{$title}\r\n\r\n" );

tests/providers/class-two-factor-backup-codes-rest-api.php

@@ -88,6 +88,36 @@ public function test_generate_code_and_validate_in_download_file() {
 		$this->assertCount( 10, $data['codes'] );
 		$this->assertTrue( self::$provider->validate_code( wp_get_current_user(), $data['codes'][0] ) );
 		$this->assertStringContainsString( $data['codes'][0], $data['download_link'] );
+		$this->assertStringContainsString( 'Two-Factor Recovery Codes for example.org', rawurldecode( $data['download_link'] ) );
+		$this->assertStringNotContainsString( home_url(), rawurldecode( $data['download_link'] ) );
+	}
+
+	/**
+	 * Verify that the download title can be filtered.
+	 *
+	 * @covers Two_Factor_Backup_Codes::rest_generate_codes
+	 */
+	public function test_download_file_title_can_be_filtered() {
+		wp_set_current_user( self::$admin_id );
+		$filter = static function () {
+			return 'Custom recovery codes title';
+		};
+		add_filter( 'two_factor_backup_codes_download_title', $filter );
+
+		$request = new WP_REST_Request( 'POST', '/' . Two_Factor_Core::REST_NAMESPACE . '/generate-backup-codes' );
+		$request->set_body_params(
+			array(
+				'user_id' => self::$admin_id,
+			)
+		);
+
+		$response = rest_do_request( $request );
+		$data     = $response->get_data();
+
+		remove_filter( 'two_factor_backup_codes_download_title', $filter );
+
+		$this->assertEquals( 200, $response->get_status() );
+		$this->assertStringContainsString( 'Custom recovery codes title', rawurldecode( $data['download_link'] ) );
 	}
 
 	/**