Site icons have a slight "bleed" on their edges
I think this is a result of me generating two spritesheets at different resolutions - one with the icons 32x32 (for higher DPI devices) and one with them reduced to 16x16. It looks like there's probably some anti-aliasing being done when it shrinks the icons down by half, and sometimes it's possible to see kind of a light "stripe" along one of the edges of the icons, from that bleeding over from an adjacent icon.
Not a big deal overall, but needs to be looked into. It might just be a configuration option in the spritesheet generator (Glue) to not antialias when it's resizing.