Last spring, 3,000 British soldiers of the 4th Light Brigade, also known as the Black Rats, descended upon the damp forests of Estonia's eastern territories. They had rushed in from Yorkshire by air, sea, rail, and road. Once there, the Rats joined 14,000 other troops at the front line, dug in, and waited for the...

This is today's edition ofThe Download,our weekday newsletter that provides a daily dose of what's going on in the world of technology. Europe's drone-filled vision for the future of war Last spring, 3,000 British soldiers deployed an invisible automated intelligence network, known as a digital targeting web," as part of a NATO exercise called Hedgehog...