ICC color profiles
The International Color Consortium defined a file format to express information about color space transforms. These files, usually found with .ICC or .ICM extension, are what the RedTitan Color Management System requires to process color space transforms.
Note that ICC files are not all the same, they can have a number of different purposes.
When the RTcms dialog is shown, or after using the 'Browse' button, the profiles found in the directory selected are loaded to check what kind they are. Each profile list is loaded with the names of the profiles that seem to be appropriate.
Each profile usually describes how to transform from the specified color space into a CIE standard colorimetric space called a "Profile Connection Space". Some profiles offer a reverse transform too, but some do not. Some rely on a reverse transform being calculated.