Where are all these "default" profiles and profile groups come from? I sure didn't name any that way.
Thanks for your question. When you use the GPU Clocking tab with the button "Apply and save for miner" it will not only apply the clocking but also create a clocking profile for this specific miner and set it to be used via the Properties of the miner. This is why you see the groups called "Default for <MinerName>".
This way you don't have to first create clocking profiles and later on specify it to be used on the miner - this button does everything.