Problems with lists and bookmarks should teach you to save important lists, etc. in multiple places

Subj.
This may be your first online occasion of this kind (especially if you're young), but it certainly won't be your last.
Personally, I was saved by the fact that several months before this, I once again saved all my bookmarks in a text file. I did this because I've lost many things (photos, lists, videos, various tag lists) due to the service suddenly crashing or losing data. I once lost my entire email adress because I hadn't accessed it for a long time (few years) (I was in the hospital for a long time, then in a foreign country without internet, and so on). Basically, nothing is guaranteed to be saved.
KEEP EVERY KIND OF BACKUP.