The logos have a code in their file name that indicates logo type, color, and the general size they are designed to be used at without becoming illegible.

For example, ANR_logo_1pbg_xs.eps gives the following information:

"_1pb"is logo type 1, process blue and gold
"_xs" can be used extra small

Here's a complete list of the codes used in ANR logo filenames

reg - regular
sm - small
xs - extra small

bw - black and white
rev - reversed, a white logo for dark backgrounds
pb - process blue
pbg - process blue and gold
sb - spot color blue
sbg - spot color blue and gold

Colors
Process blue - C=100, M=70, Y=0, K=0
Process gold - C=0, M=20, Y=100, K=0
Spot color blue - Pantone 286
Spot color gold - Pantone 115 (uncoated paper), Pantone 116 (coated paper)