You must enable javascript in order to use the Slack API Documentation. You can do this in your browser settings.
Go to Slack

pref_change event

You have updated your preferences

Compatibility: RTM

    "type": "pref_change",
    "name": "messages_theme",
    "value": "dense"

The pref_change event is sent to all connections for a user when a user preference is changed. Clients should update to reflect new changes immediately.