If there was no saved to restore feature then there is no bookmark to restore.

If you notice you lost bookmarks and a search in the Library doesn't find them in case you accidentally moved them to another folder and you haven't closed Firefox then try "Organize > Undo" in the bookmarks manager (Bookmarks -> Show All Bookmarks) to undo this action and restore bookmark(s) you deleted accidentally. Note that you may have to use Undo more than once (Firefox keeps a full undo history). Otherwise you can consider to restore the bookmarks from a JSON backup in the bookmarkbackups folder.

• Bookmarks > Show All Bookmarks > Import & Backup > Restore

This will replace all current bookmarks and you lose bookmarks that were added since that backup was created.