Created attachment 9225 migrate_goodies_url-calculator-plugin.patch The attached patch updates the URLs from goodies.xfce.org to docs.xfce.org.
Kevin Bowen referenced this bugreport in commit bb038a4975ac89700af8892c9034c147cbfaaf2b Update URLs from goodies.x.o to docs.x.o (Bug #16155) https://git.xfce.org/panel-plugins/xfce4-calculator-plugin/commit?id=bb038a4975ac89700af8892c9034c147cbfaaf2b