If you need to see all the whitelists (open, closed, expired etc.) on your Discord server, use the command /configure-whitelist list. It will show all whitelists and their times and conditions in one list.
In addition to your own whitelists, it will also show whitelists that other servers have shared with you, and which server they belong to. No additional information about shared whitelists will be available, but the signups can be downloaded via /configure-whitelist download.