The Bnd... .gdb file was created with Peter Hutchin's program using these commands:

las to raster, rasterdomain, raster to polygon

Essentially, they create a boundary file that shows exactly where the las points exist, 
and where the tile extents are.  
To see the las boundary, in definition query, use:
extentpoly = 0

It is better and more accurate then the digital coast or COE tile index. 

B. Yassin 11/23/2015