Think of it as a factory restoration image. For the STL100-2, the official final Autoloader is named: Z10_STL100-2_10.3.03.3216_ .exe (or similar, depending on the software release number).
The "10.3.3" you are looking for generally refers to the final build released publicly. The specific software release version you should look for is . Blackberry Z10 Stl100-2 Autoloader 10.3.3 Download
– Windows is required (the autoloader is a .exe file). Install the necessary USB drivers if not already present. Think of it as a factory restoration image