Create a copy before moving
Open My List and choose Create backup. The box below the button will contain a complete text record of your saved selections and supported checkpoints. Copy all of it into a note or document you can access later. Keep the opening and closing characters as well as the title identifiers; an incomplete copy cannot reliably restore the list.
Merge in the browser you want to use
Open M4uHD in the destination browser, go to My List and paste the backup into Restore backup. Choose Merge backup and read the result message. Titles already saved are not added twice. If that browser already has a checkpoint for a show, the existing checkpoint is kept instead of being silently replaced by an older copy.
What stays outside the backup
The backup does not contain movie files, another service’s account, a password or a cloud playback history. It does not transfer recently browsed pages or the viewing country. Those are separate browser preferences. Unknown titles or invalid episode entries can be skipped, with the result reported, rather than being turned into broken saved items.
If saving fails
Check whether the browser permits website storage and whether a private session is about to close. Keep the original backup text until you have opened the restored list and checked an important checkpoint. Do not erase the only working copy as part of a test. You can remove individual saved titles later from their detail pages.