Required header Filename extension for this file type. May be NULL if no filename extension exists and/or is known. For file types that match several common extensions, list them in a comma separated list such as: "pdb,ent,foo,bar,baz,ban" The comma separated list will be expanded when filename extension matching is performed. If multiple plugins solicit the same filename extensions, the one that lists the extension earliest in its list is selected. In the case of a "tie", the first one tried/checked "wins".
Referenced by VMDPLUGIN_init().