[UPDATE]
Problem solved. It's TripMode. Unload system kernel module with:
launchctl unload /Library/LaunchDaemons/ch.tripmode.TripModeNKE.plist
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On Safari Extension Gallery page the "Install Now" button does not appear after updated to Sierra 10.12.4. It seems that Apple's official...
The 15-inch 2011 MacBook Pro is something that Apple and AMD both probably wish to put behind them. However, for those that own the computers, doing so isn't quite as easy, because they are aware that they have a fully functional computer, minus one part, and that the system itself ironically...
My 89-year old father-in-law is in the early stages of dementia and uses his credit card to buy a lot of random unnecessary crap online.
I wrote this Safari .js extension to pop-up a warning when he opens a new window, warning him about using his credit card.
function watchOut() {...
On Chrome there are dozen of extensions that allow youtube video to be played "full-window". the player width will match the browser window width.
But on Safari I can't find such extensions.