Hi Phoebe,
the plaque was revealed during the closing ceremony. I understood it is connected to the collaborative space (how typical) of the village, to commemorate that Wikimania was in the town. I'm not sure if the space is actually named after Wikimania, that part of the translation got lost on me. The wiki says however: "Esino Lario collaborative space devoted to the associations of the village and named after Wikimania"
The artist was there too, I think, but I didn't catch many details.
Lodewijk