Goldilocks is a tool for identifying where you have too much or too little Resolution in your Textures for a given viewpoint.
The last part is important because if you're far away from a textured surface you need less detail than when you're really close up. Having too much resolution just increases file size with NO INCREASE ON QUALITY for rendering with LightUp or any renderer - including raytracers. Its simply a waste of space.
For realtime products like LightUp where you can move anywhere you like, you might wonder whats the point. Well even though you can move "anywhere", the reality is that you'll have known places you'll be wanting to explore and Goldilocks is a handy tool for finding places where you've gone a bit nuts on Resolution. In particular, you do want to keep "Texture density" roughly constant around your model - having very blurry low resolution textures next to super crisp high resolution textures can be very off-putting.
So move around your model and right-click / choose from the Tools menu the "Goldilocks" item and it will analyze your model from your current viewpoint and come up with a sorted graph of all your textures showing which are too high resolution, which are just right, and which are too low.
Bars in red are textures that have too much resolution.
Bars in green are just right
Bars in yellow are too low.