Warning (instead of blocking) is possible. Due to the security logging (plus, if wanted, SIEM integration) you get the flagging.
Can you run data through a local or corporately-situated LLM instructed to "Assess whether this looks potentially sensitive" via a given set of rules, and flag it to the user or a supervisor to proceed/abort?
Not in the first version, but this is an area we are working in.
what kind of hooks and feedback/UI interaction is available for third party integrations?
We support the standard SDK for this which is also used by Chromium based products:
https://hacks.mozilla.org/2025/03/improving-firefox-stabilit...
That's how Trellix and Broadcom integrate with it as well.