What is an "anti-smudge" screen?

So, I've come to understand Lenovo's ThinkPad screen terminology as follows:

• Anti-Reflective: Glossy
• Anti-Glare: Matte
• Anti-Reflective Anti-Glare: Matte that kinda looks Glossy from a certain angle

But then there's anti-smudge. You can get Anti-Glare Anti-Smudge (AGAS), or Anti-Reflective Anti-Smudge (ARAS). I've seen an ARAS and regular AR screen next to each other in person, and they look no different - they just both look glossy. What is the "anti-smudge" doing?

Furthermore, I can't tell the difference between an Anti-Reflective screen and a "Glare" screen (which exists for some rare ThinkPads and Lenovo's other laptop lines), which further adds to the confusion. The so-called "anti-reflective" screens sure do show a ton of reflections. Not that I'm complaining about that, I personally love glossy screens. But the names are confusing for sure.