"Unfreeze Model" and "Freeze CLIP Normalization Layers"

[morphinapg]

What exactly do these options do, and what effect do they have on training? Wouldn't a frozen model mean it couldn't be trained? Yet it does train just fine without selecting that option, so is it only unfreezing a specific part of the model? As for CLIP Normalization Layers, what benefit would there be to freezing them? I would imagine that would at least partially get in the way of training CLIP to understand the wording you use in your prompts, yet the text encoder does in fact still train even with that option enabled, so once again, I'm having a hard time understanding exactly what's going on there and what effect it's having on the model.