In 1949, the United States initiated the Mutual Defense Assistance Program. Allies and potential allies were provided with various kinds of monetary and materiel support in an effort to build up their defenses against the perceived threats of the Cold War. Many countries received tanks, most of which were WW II surplus.
Sherman variations were created specifically for the MDAP program – the M4A1E6 and the M4A3E4. The M4A1E6 was a “small hatch” M4A1(75) with VVSS in which the original 75mm was replaced with a 76mm gun.
Surviving M4A3E4s are most numerous in the countries that once made up Yugoslavia. Perhaps the most famous examples are the ones featured in the 1970 film “Kelly Heroes”.