What does it do?

Allow to show widget with 10th anniversary link to selected city.

Yes, this you said already. The trick for software development is to recognize that people see things from different perspectives. Please help me to understand what you are saying, since I don’t have all the information you assume in your own head.
Sincerely.

The date: https://www.ads-software.com/news/2013/04/save-the-date-may-27/

And a anniversary events: https://www.meetup.com/WordPress/

Thank you ??