Hello everyone, this is not a Sparkle problem, but a Safari issue. For the past few weeks, after the latest update, Safari icons related to websites are no longer displayed in the address bar. Is this happening to you as well? I am on Sonoma 14.7. Thank you.
From my latest experience this is an Apple thing with their latest Safari builds. In fact this has been an ongoing issue for the last 2-3 years if your check the Apple forums.
I have all my favicons showing in the open tabs, but definitely not anymore in the URL bar.
Just another Apple call to make them stand out different! 
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If there is truth in this latest matter (I’m still hunting up information) then the latest Apple macOS won’t allow us to download applications from independent websites? Boy, I hope that is not true!!! What it means is that I won’t be able to download Sparkle via the Sparkle App website, only through Apple’s paywall store. I really hope this is not true because Apple will be known as a rotten apple!!!
As a looooonnnng time Mac software developer, who’s been providing software via private distribution since before System 7 and Mac App Store distribution since it’s inception, I’d expect to be notified 'way in advance if such a limitation was being implemented. And it hasn’t. This has the curious ring of propaganda.
In fact, Apple has recently been adapting to requirements in some parts of the world to allow the reverse in the iOS world - ad hoc distribution outside the App Store. I am, however, as a registered Apple developer, a big fan of Apple’s notarization capabilities which provide a level of curation of my software to certify it’s from me, and safe for use on Apple devices.
Thanks @JBTexas for your take on it! 
As I mentioned I am still looking into this to further understand what it means.
So far I have read the following plus a few others - Shared post - Apple Removes Ability to Run Unsigned Apps in macOS 15.1 For me it is a sign where Apple is going to lock down macOS like they have done with iOS. But time will tell…
That’s not really what this thread was about originally, but Sparkle is distributed outside of the appstore in the Apple sanctioned way (signed and notarized). Some free software is distributed without the Apple signature, because that requires paying Apple’s developer program ($99/year), and for money or ideology reasons the developer doesn’t want to pay it. This software could be opened either by relaxing the system security, or by right clicking on the app and selecting Open. This ability has been removed.
A signed/notarized app infrastructure lets Apple react quickly in case of malware, blocking it as it starts spreading. It’s one of the reasons Macs still are more secure than Windows machines.
It also means Apple gets to impose their policies on developers, not always great, but it’s not a concern for Mac users.
Should they ever block non appstore apps, I hope they’ll recognize that there is a ton of non-appstore software around, and they’ll provide some migration path. Honestly I don’t think this will happen anytime soon.
With Sequoia (15.1), the active site will have the icon for the reader display at the left with the favicon in the tab below. If you click on the address bar, however, the favicon will be displayed at the left side.
I think that is how 14.7 worked as well but I was forced to move on to Sequoia when my logic board died.