Official BlackBerry servers are no longer active, so you must rely on community archives. Internet Archive (Wayback Machine) : Houses a collection of original BB10 autoloaders. CrackBerry Forums
According to technical forums, the Leap (STR100-x) and the Z30 (STA100-x) share the same hardware architecture. Consequently, you can safely use a Z30 autoloader file for your Leap. The OS files are identical. Blackberry Leap Str100-1 Autoloader Download
Unlike standard updates, an autoloader interacts directly with the device's bootrom. When executed on a Windows PC, it searches for a connected BlackBerry in boot mode and forcibly writes the OS partitions. This is the most effective method for fixing "bricked" devices (those stuck in boot loops or with corrupted OS files). Official BlackBerry servers are no longer active, so