The home page (an xowiki page) is set via the parameter IndexRedirectUrl, but if an anonymous user tries to view the page he is redirected to the registration page.
Other applications where I granted read permisssion to the public (i.e. news) work as expected, and so I suspect that the registration is requested by xowiki. I think it shouldn't be so, for a site to be visited by the public.
In previous versions of xowiki there was the view.tcl to look at, but now the rendering of the page is managed by an object's method and my actual knowledge of xotcl leaves me down.