What's the "Additional ML" in the add-ons option?

“Additional ML” = extra model files that the app can download and use locally to run AI features quickly and/or offline. 

If the models aren’t installed the app may either fall back to slower/local heuristics, require cloud processing, or show the feature as unavailable. 

These models are what Adobe Sensei / Adobe’s AI features rely on (roto, content fill, some generative/auto features).