It seems Gmane is no longer online: https://lars.ingebrigtsen.no/2016/07/28/the-end-of-gmane/ Unfortunately, the lua-l archives have many links to gmane.comp.lang.lua that are now dead. I don't think it is possible map gmane.comp.lang.lua message numbers to the corresponding ones at lua-users.org/lists/lua-l/ . The MARC mirror at http://marc.info/?l=lua-l is still online but I'm not sure how many people use it. I only found a couple of links to it in the entire lua-l archives.