Weeks of high-wire negotiations between China and the EU culminated in a surprise trade deal that will, among other measures, impose strict quotas on Chinese hybrid car exports to the bloc and slash Chinese tariffs on a variety of European goods. The deal, unveiled on Friday, takes some of the heat out of searing bilateral trade tensions and temporarily averts the prospect of a bruising trade war. Beijing agreed not to retaliate against Brussels’ move to curb imports of Chinese hybrid cars,...