Perhaps @alex could answer this considering your report on 0.15.3**
Unlike most of my topics I’ll keep this very simple.
Opening any sort of New Tab and or Minimize should discreetly activate a Kill Switch.
Similar to right-click and Open Tab in New (any sort tab) which doesn’t necessarily fully load the content, what’s the point of keep a tab in data usage mode when you’re not going to be using for more than half an hour if you’ve got more than a dozen or so tabs open.
I imagine there will be a small discrepancy relating to essential websites which require to be in memory such as a web service but I think this particular feature further opens the door to another feature which is a GUI based Tab.
Essentially, relating to the topic at hand for the moment, Brave should either intelligently deduce that a particular web service such as email needs to remain active or allowing a GUI based Tab function which allows a user to sort of move the mouse over the Tab to keep that active.
I suppose you can divide the the new GUI based tab into two/three parts, the ‘x’ to remain where it is and the Lion icon side of it to do the necessary functions described.
I suppose if thought was put into it, it will have to be as a setting feature.