BRB in this case actually stands for
Big Rusty Box
I know you were thinking it meant Be Right Back as in the common usage in e-speak.
Here are a few other of the common e-speak acronyms:
ttfn (this was actually coined by Tigger pre-internet)
There are many others, share them in your log if you wish.
If you have any idea about the "who what why when where or how" of this object, post it.
Not recomended as a night hunt because it will draw undesireable attention from the Border Patrol.