Feature Request: Private Windows
I don't know if this is possible to achieve or not, but here it goes.
Feature summary
Private windows feature for screen sharing and screen recording.
When an app requests or has some property that indicates it has sensitive information, do not render it for screen recorders and screen sharing protocols, but do show them on screen. Apps that may fall under this category are Slack, Private Browsing Windows and WhatsApp Web wrapper app.
How would you like it to work
I may be wrong about how things work here by a long shot.
Mutter renders all windows on the displays available but looks for each window's privacy
property when rendering for screen sharing or recording apps. Apps will be required to set this property (is this possible in GTK at least?) independently.
Relevant links, screenshots, screencasts etc.
This is a feature in Android. See this image for reference: