That’s not suspicious, that is the normal port for it to run on. It is not typical that they would include the port number but they may use a different one for testing and automatically change it or something.
Firefox
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That is normal https port, some websites may reference it directly while others skip it, it is fine. You can edit permissions on a per site basis to always ask, block, or allow location access by clicking on the lock icon > Connection (secure/unsecured) > More Information, then change to Permissions tab and set it how you want.
If tired of being prompted about location on all sites you can go into Settings > Privacy & Security, scroll to Permissions, click Settings next to Location, click 'Block new requests' and save changes. Per site allow/block/ask can still be configured.
Blocking it browser wide worked, but it is a bit inconvenient; the site was prompting everytime i was just browsing it even though i clicked remember the decision.
Is it always exactly the same site URL?
Yes