Forum OpenACS Development: Weird comment on singleton_p

Posted by Andrew Piskorski on
In "packages/acs-kernel/sql/*/apm-create.sql", this is the comment on column apm_package_types.singleton_p:
Indicates if the package can be used for subsites. If this is set to 't', the package can be enabled for any subsite. Otherwise, it is restricted to the acs-admin/ subsite.
My immediate thought was, "Huh?". What the heck does that mean? What do subsites have to do with the singleton-ness of a package? And the "acs-admin" subsite, what? I've sure used non-singleton packages in other places - like the Main sub-site at "/", for instance.

That comment has been in there since ACS 4.2, actually, but I never happened to look at it before. And I've missed some stuff anyway, since I haven't been paying any attention to low level details like this in OpenACS since ACS 4.2, so could someone fill me in: What should that comment really say? What are the true ramifications of singleton_p in OpenACS?