In case you do not know: We usually do not repeat information inside the database when this information can be obtained in a straightforward manner.

Example for De Panne.
The OSM object for this town contains a wikidata tag, pointing to this page: https://www.wikidata.org/wiki/Q674954
Wikidata is the central repository for a lot of information, so it does not have to be replicated into OSM.
The "official_website" property of Wikidata already stores the URL of the website.