AutoLOD | Automatic LOD generation + scene optimization | Game Engine library

That is actually only one autoloader, the array is a callback.

ComposerAutoloaderInit374429f4ab4935127e2d36a0613c8d3a is a name of the class, loadClassLoader is the name of its method to be used.

The class is defined directly in autoload_real.php file, the method is the first method in the class.

You are on the right track: The -o option creates an "optimized" autoloader that essentially is a classmap for every class that otherwise would be loaded through PSR-0 or PSR-4. Composer will scan all directories that are mentioned for PSR-0 and PSR-4 just like it would always to with classmap entries.

This might already answer your question: If your project only has a classmap entry and nothing else, there is no difference in the result.

Note that it is not the best idea to prematurely optimize the autoloading by forcing the classmap if you could also use one of the PSR schemes. Using only the classmap will hinder development because every time a new class is created, you'd have to dump the autoloader with that new entry. Also note that creating huge classmaps might actually be slower than PSR-based class loading, because you trade code execution time for allocated memory, and at some point allocating memory for all classes in every request even if they are not being used will be slower than executing PSR autoloading. You'd have to measure your individual application performance with both a normal and an optimized autoloader to decide which one is actually better.

More info in the docs