The entry point main.cpp file is the entry point to your application. It's automatically generated by the UVKBuildTool under the Generated folder. It looks like this:

// This is an autogenerated file, touching it is not recommended
#include <Framework.hpp>
#include "."
#include <Global.hpp>
#include <Renderer.hpp>

int main(int argc, char** argv)
    PRJNAME::Instance instance{};
    instance.argc = argc;
    instance.argv = argv;

    for (int i = 0; i < argc; i++)
        instance.arguments[i] = argv[i];
    UImGui::Utility::getGlobal().instance = &instance;

    UImGui::RendererInternal renderer;

First it calls the startup macro, then initialises the instance, fills it up with the CLI arguments, sets the instance to the global class then starts the renderer.