File saved by the Mac version of Adobe Photoshop before Photoshop used file extensions on the Mac; 8PBS is actually the file type code listed in the Type/Creator part of the file and may not be an actual extension.
Program(s) that open 8pbs files
Mac / Windows: Adobe Photoshop
Information from FileInfo.com - The File Extensions Resource.
http://www.fileinfo.com/extension/8pbs
