To specify a single .ditaval file that applies to your entire DITA document:
[ConditionOptions]
; DitavalFile = path to ditaval file to read.
DitavalFile = d:\path\to\my.ditaval
When you specify a value for DitavalFile in your project configuration file, for HTML output DITA2Go combines each attribute name and value to form a class name for use in the file designated by CSSFlagsFile (see §9.3 Including flags for ditaval conditions); for example, platformlinux. This setting is ignored for RTF output.
If your project configuration file does not specify a value for DitavalFile, instead DITA2Go uses values specified in the [Conditional*] sections described in §9.3 Including flags for ditaval conditions.