All these are clear. The wedding officiant isn’t saying “You might have permission to kiss the bride! Just try it and we’ll find out! Ha ha!”
To interpret this as saying that you might be licensed is just as nonsensical as that in this context. It’s in a file named “LICENSE.txt” explicitly meant to describe the license terms.
Would ‘are’ be better? I’d say yes, but it’s silly to argue that this isn’t proper English for granting permission.