There’s Zotero. I haven’t used it but seems to have a feature called ‘Collect with a click’ which should allow adding bookmarks.

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No prob! 😊 👍️

Thank you, I’m pretty proud of myself as well. I was already prepared to re-install from scratch, because I have backups in place. I still can’t understand why a tiny programme completely borked Software Center, but apparently Windows and Linux don’t mix at all, unless you use Wine.