> relicense under 3-clause BSD under BSD or GPL anyway.  So, unless I'm
> missing something, the "or GPL" probably doesn't do anything more than
> make explicit something that was allowed already.

not entirely; in a dual license scheme one has the freedom to ignore one
of the two licenses and also to place derived work only under the one
chosen. That and it's outright rude to take someone else's code and
relicense it.