I think they mean https://www.collaboraonline.com/. That’s what’s used if you install the office addon for Nextcloud, if I’m not mistaken.

My JSON export from wallabag is 46 megabytes. That’s for 2,465 articles.

I love how active the development on Linkwarden is. I still have all of my stuff in wallabag, but Linkwarden is tempting. I gave the hosted trial a try a few weeks ago, but my wallabag export was too big to import. Maybe I’ll try selfhosting it and manually increasing the max upload size this time.