Thanks for the post!
Yes you’re right, unfortunately this functionality was lost with the recent Trove upgrade. I’ve been looking at ways of restoring it, but it’s not easy. Previously there was a Bibtex formatted citation that Zotero could use to extract the bibliographic information, but that’s no longer accessible. There’s an internal API that has the citation info, but you need a key to get it. The only other option is to try and scrape the details from the Trove web page, but the HTML is not usefully structured, so that’s going to be difficult and prone to error.
Anyway, I’m really glad to know that people want to be able to do this! I wasn’t sure whether it was worthwhile spending the time to make it work, but this will give me some added motivation.
And yes, wouldn’t it be great if GLAM interface developers thought about things like embedding structured data in their pages for tools like Zotero to access! I actually just submitted a suggestion to SLNSW for their new catalogue along those lines. You might like to do the same.