Hi Maarten,
on this page you can see the text:
https://ticinovivo.ch/attivita/ristorante-sasso-grosso-locarno-copia/
The problem here is that it’s just wrong Italian. I guess you used a translator. I am a native Italian speaker, so I can assure you that the phrase itself is wrong.
This is a perfect translation from English into Italian because the perfect translation from English into Italian is: It’s Wednesdays, which in Italian would be “sono le mercoledì”.
But the verb is wrong. So the right phrase would be:
“È mercoledì ore xxx” or “Sono le ore xxx di mercoledì”.
I hope I’ve been of help to you, and if you need corrections or complete the translation of your fantastic plugin, you can count on my help.
Thank you
Raffaele