Create a copy
Open My List and choose Create backup. Copy all the text shown in Your backup, including the opening and closing braces. Keep it in a private note or another place you control. The text describes saved choices; it contains no movie files.
Merge on another device
Open Supernova in the other browser, go to My List and paste the complete text into Restore backup. Choose Merge backup. Recognized titles are added to the existing list. Current checkpoints are kept when a backup also contains a checkpoint for that title.
Read the result
The message reports additions and skipped items. An incomplete paste cannot be restored, and a backup from another brand is not interchangeable. Keep the original copy until you have checked the resulting list.
Use this before clearing site storage or changing browser profiles. A home-screen shortcut does not create automatic cloud synchronization. Open My List to create or restore a copy.