The Pixel Bender Graph file stores kernel source code. It uses XML format. Source code has CDATA tags. This preserves formatting. Pixel Bender kernel files use .pbk extension. PBG files do not have .pbk files. But PBG files have kernel source code.
Windows uses Adobe Pixel Bender Toolkit for PBG files. Mac OS also uses this toolkit. The toolkit makes image filters. Filters work in Photoshop, Flash, and After Effects. PBG files connect filters into one unit.
Windows links PBG files to Pixel Bender Toolkit. If the link fails, Windows cannot open PBG files. To fix, link PBG extension to the toolkit. Or use a file opener for PBG files. Some files have plain text data. Text editor apps can open these.
Adobe After Effects
Pixel Bender Toolkit