.OFP File Extension

An OFP file is a theme file created by Origin, a data analysis and graphing application used by various scientists and engineers. It contains settings in XML format that configure a function in an Origin function plot. OFP files may include points, definitions, and formulas that appear in a function plot.

You most likely will never encounter an OFP theme file when using Origin since the files are created and loaded through the app. If you want to open an OFP theme file, you should place it in the "Function" folder of the C:\Program Files\OriginLab\Origin<version>\Themes installation, then load it using the function plot window in Origin.