As you can see in README.txt in CY8CKIT-050B_Gerber filefolder.
Instructions to view gerbers:
GraphiCode, Inc. provides a freeware gerber viewer, GC-Prevue, available
for download at te following URL:
Once this application is installed you can view the *.art files by
using the "File | Import" function.
Cypress uses a .art extension for gerber files. Gerber files are ASCII
text and are easily identified to someone "learned in the art."
my problem is not with Gerber files i did open them using program special for Gerber files .
my problem is with CY8CKIT-050B_Board_Layout.brd this is as i thought Eagle extension but it's corrupted.
Oh Sorry for my mistake. You may use Allegro PCB Designers to open the .brd of KIT-050.
Eagle can open some .brd files but the brd generated by Cadence may not be able to be opened by Eagle..