CSSCheck

[keyplyr]

UA: CSSCheck/1.2.2
Protocol: HTTP/1.1
Robots.txt: No
Host: AWS
54.72.0.0 - 54.95.255.255
54.72.0.0/13, 54.80.0.0/12

If I had to take a guess, I'd say this was checking CSS.

[lucy24]

I'd say this was checking CSS

Société Canadienne du Sommeil, aka Canadian Sleep Society? Who knew? It's good if your site is slow to respond; it means you're asleep when you're supposed to be.

[keyplyr]

Long way to go for an acronym, eh?