.EFTX File Extension
File TypeOffice 2007 Theme Effect File
What is an EFTX file?
Theme effect that can be applied to presentations and documents in Microsoft Office 2007 or later; contains effects that may be applied to charts, SmartArt graphics, tables, pictures, shapes, WordArt, and text; includes effects for lines, fills, and special effects, such as 3D and shadow effects.
EFTX files contain a subset of the data stored in .THMX files. To create an EFTX file from a THMX file, remove the slideMasters, slideLayouts, and _rels folders from the theme top-level folder in a THMX zip package, and then rename the file with a ".eftx" file extension.
EFTX files are commonly used across multiple Microsoft Office documents and presentations to maintain the same look and feel. They are not available in Office 2008 for Mac.