Toast notification shows "Silence alarm" for notifications that don't have an alarm

[blammit]

Go to Settings > General > Access & Security > Access Level. Change the access to "User" and enter the wrong password. An error-type notification appears with an unexpected "Silence alarm" button:

This also occurs for warning-type notifications, e.g. when the Brief side panel is closed as the CPU is too high.

Can also be tested with the buttons in Settings > Debug & Develop > UI Library > Toast.