I found yet another bit of flotsam or, perhaps, jetsam -- a very nice light -- in the shallows of San Carlos Beach (aka the "Coast Guard Breakwater”), attached to the colorful lanyard, seen above.
Some initials or code had been written on the body: "BRE L2."
If you can identify what was attached to this day-glow yellow lanyard, in specifics, it is yours . . .