... Note that this method is called by TWiki and configure, and only reads TWiki.spec= to get defaults. ... The assumption is that configure will be run when an extension is installed, and that will add the config values to LocalSite .cfg, so no defaults are needed. ... This is only called by configure to initialise the TWiki config hash with default values from the .spec files. ... However when configure runs it has to get default values for config vars that have not yet been saved to LocalSite.cfg . ...