Download the APK file.
Install the APK. You may be prompted to allow installation from unknown sources. The app can be scanned by Play Protect for safety.
Open Settings on your device, go to Apps > Default Apps > Browser App, and select Clippy as your default browser.
Now, whenever you click on a link that would normally open in a browser, Clippy will automatically copy the URL to your clipboard without opening it.
When you’re done, don’t forget to change your default browser back to your preferred app.