For your default search engine, the Safari address bar displays your search terms rather than the search engine URL
You can specify your default search engine in Safari Settings.
In Safari 18 and earlier, when you copy and paste from the address bar, for example with the ⌘C and ⌘V keyboard shortcuts, the result is a URL, https://duckduckgo.com/?q=StopTheMadness+Pro&t=osx&ia=web in this case. In Safari 26, however, the result is simply your search terms, StopTheMadness Pro in this case.
If you open the Safari 26 contextual menu on the address bar, you can see two menu items, Copy Search Terms and Copy Link, whereas in Safari 18 and earlier there is only a single contextual menu item Copy, which copies the link URL.
The same change in behavior has occurred from iOS 18 to iOS 26. On the former, the Safari address bar contextual menu includes a single Copy command, which again copies the link URL.
Whereas on iOS 26, there are two contextual menu items, Copy Search Terms and Copy Link. Notice the visual glitch in Safari private windows where the search terms are missing in the selected address bar, because Liquid Glass is half-baked.
On macOS, you can use the developer utility Clipboard Viewer app to see what’s happening at a technical level. Clipboard Viewer is part of the Additional Tools for Xcode, an optional download available to registered Apple developers. When you copy the address bar in Safari 18, the pasteboard item of type public.utf8-plain.text is the search engine URL, but in Safari 26 it’s the search terms. With both Safari 18 and Safari 26, the search engine URL is available on the pasteboard as type public.url, but when you paste into a text area, the text type is preferred.
In my opinion, the contextual menu change is fine, indeed an improvement, but the keyboard shortcut behavior is a downgrade. When copy was separated into two commands in Safari, Apple had a choice to make with regard to the copy keyboard shortcut, and in the immortal words of Judge Yvonne Gonzalez Rogers, “Cook chose poorly.” (That’s a joke. Tim Cook probably wasn’t involved directly.)
The good news is that my Safari extension StopTheMadness Pro has an option to copy the page URL when you use the ⌘C shortcut. However, this feature works only when the web page has the focus, not the Safari address bar, because Safari extensions have no direct access to the address bar.