View and remove notification messages from Apple's "Notification Database"
Background:
"When Disappearing Messages Don't Disappear: The 'Dark' Side of (macOS) Notifications"
AuRevoir (French for 'goodbye') is a simple utility to view and remove notifications from Apple's Notification Database
The application targets Signal notifications -but, click 'all apps' to either view or remove all notifications:
Download: "AuRevoir.app"
Note: the 'Remove' functionality will modify the system Notification Database ($TMPDIR/../0/com.apple.notificationcenter/db2/db*)