How to change the browser of a web-shortcut? An incompatibility between F-Droid's current version of IceCat and Android 8, makes it that I can't Add to home screen from IceCat (well, I can, but it doesn't do anything other than jump back to Trebuchet).

How can I create a web-shortcut to IceCat in that case?

I figured I could create a web shortcut with another browser, but it seems those shortcuts are "bound" to their original browser, so even though IceCat is my default browser, the web shortcut opens up in another browser.

Maybe another way to ask this, is: how to create a web shortcut which is not specific to any browser, so when I click it I get asked which browser to use.
Try Website Shortcut. Open the app, paste the link of the website/webpage, then click on create shortcut. It will fetch the icon from the website for you.

On the home screen, click on the shortcut, you will be prompted to choose a browser. After selecting your browser, I advise to select "Just once" to allow the selection of other browsers if needed.

The disadvantage of the app is that if you remove it, the shortcuts will also be removed.

Disclaimer: I am not related to the app's developer.

EDIT: Below his the response I received from the app's developer as to why the source code is unavailable. He has given his authorisation to show the screenshot of his response.