These file is decrypted and ready to use, but if you need to understand how you can decrypted other Themes with the file ending .edat you need the RAP file and the PS3 Edat Tool. Open the App and load the .edat and the RAP file and than start the decryption. The program give you the message "COMPLETE: File Written to disk". Normally its the self direction from the .edat or the RAP file. There you find a new file with the ending .dat. Rename this file to .p3t and thats it.
So you can use it as a normal .p3t theme (put it on a USB Stick with direction USB:\PS3\THEME and then Settings ==> Theme Settings ==> Design and click on the bar that now appears to be high on Install ==> USB flash drive / memory card / etc.. So you can use it on an OFW) without any RAP file in exdata direction
Or use a FTP app to copy the Theme in the Theme directory.
Africa Zebra Dynamic PS3 Theme is a beautiful idea. This theme is based on natural beauty. I like your theme because natural beauty always fascinating to all. Nice theme and you did select good picture of zebra.