The portal, page by page
Monitoring
Titled "Chat monitoring" (owners and admins). Settings: turn on classification of each human message (off-topic, abusive or wasteful ones are emailed), Alert email, Sensitivity (Lenient, Standard, Strict) and Per-user cooldown (minutes). Flagged chats lists flagged messages with category, severity, who sent it and a snippet.
Gotcha: the Alert email here is also where low-credit warnings, "work is paused" notices, guardrail blocks and tool-outage notices go when Slack can't take them. It starts as the sign-in email of whoever created the workspace (they also get the welcome email there); change it if alerts should go to a shared inbox.