An ACF file (for Atom Configuration File) is a file which contains the information common to all CueSheets. One such file is written per project.
The ACB files refer to the ACF file. Therefore, when an ACF file is updated, it is necessary to update all the ACB files as well.
By default, the ACF file is generated with a name following "Project name+.acf." If you want to use a different name, set the output name to ACF file name in Global Project Settings.
The ACF file is generated at the same time as the ACB file(s).

The following figure shows the relationship between the ACF, ACB and AWB files.