Root [International] sleep mode or summat?!

[simes6600]

ok, so this isn't a big prob, just summat that i wondered about since getting the S4. when i unlock it every now and then, my lockscreen is dim, with what looks like bubbles in the background, with just the clock, and 3 icons below, messaging, email and summat else. unlocks fine. am wondering is this app or rom related? had a google and came up with nowt.

and prob not "root" related, but i thought i'd post in here for the fellow nerds to have a ponder