Recover lost data from browser version?

Hi folks, We use logseq at work, and I have a colleague that has been using the web interface version of logseq, and they just noticed that their notes haven’t been being stored in the local folders since March (:tired_face:).
The web interface has been showing them, until yesterday, when they started appearing as empty (when they navigate to a previously populated page, it’s empty).
Any suggestions on where to start trying to recover them? Presumably they must’ve been being saved in the browser cache somehow? (:sob::man_facepalming:)