A boardview is the component placement map of the PCB: click a part or a net and the viewer highlights where it is and what it connects to. Used together with the schematic to find test points.

Tools to open these files

Format	What it is	Open with
.bdv	Honhan .bdv boardview	OpenBoardView, FlexBV or Honhan BoardViewer
.pdf	PDF schematic	any PDF reader; Sumatra PDF and Foxit handle large schematics well
.rar	RAR archive	7-Zip or WinRAR