CM Restore a Single Database has a line:
You can also manually manual-restore-from-backup that seems similar to OM Restore a Single Database but OM links to Restore a Database or Collection from a Manually Created Backup Instance and CM has that link removed in the "On this page" box.

Note also that there is no link for Single Database on CM Manual Restore Procedures but there is for OM.

It is likely that using mongodump/mongorestore against a snapshot is no longer supported on CM so this should be checked with PM prior to modifications. If this is no longer supported it looks like in the CM docs:
1. You can also manually manual-restore-from-backup should be removed.
2. Single Database on CM Manual Restore Procedures should link to Restore a Single Database

If using mongodump/mongorestore against a snapshot IS still supported in CM a section similar to OM Restore a Database or Collection from a Manually Created Backup Instance should be added back to CM.