Syria's long-running civil war has been off the radar for a while, but the stunning, out-of-the-blue capture of Aleppo—the nation's largest city—by rebels has changed that in a hurry. Those catching up with events will have to get familiar with a new acronym,

Amid the ongoing unrest in Syria, the rise of rebel groups like Hayat Tahrir al-Sham (HTS) poses new challenges for Israel’s security. With HTS gaining ground near the Golan Heights, concerns are growing over chemical weapons and advanced arms falling into hostile hands.

The Syrian rebel group Hayat Tahrir al-Sham (HTS), which seized Aleppo in a shock offensive over the weekend, is an Islamist movement that has long ruled