Create the backup before changing browsers
Open My List in the browser where your titles are saved. Choose Create backup and copy all the text from the output box into a note or document. The text contains saved title references and checkpoints. It is not a video download, a password export or a cloud synchronization request.
Restore with a merge
On the browser you want to use next, open My List and paste the complete text into Restore backup. Choose Merge backup and read the result. Known titles can be added without duplicating existing saved entries, while existing checkpoints stay in place. Unknown titles or invalid episode numbers are skipped rather than silently inventing records.
Keep the old copy until you have checked
Open a saved title and inspect a series checkpoint after the merge. If the backup text is incomplete, correct the pasted text and try again. Do not clear the original browser merely because you created an output box; first confirm you kept a usable copy. Private browsing and storage restrictions can prevent a list from surviving a later session.