The DCL -f switch specifies the output format, with an optional suffix that generates additional processing for certain formats.
The -f options have the following meanings:
Where listed under Suffix, you can append one of the following letters to the format name (case does not matter). These suffix options apply to HTML-based Help systems for which DITA2Go can generate contents and/or index. For example: -f HTMLHelpB.
B - Merge both contents and index
Letters C, I, and B represent three mutually exclusive options for the same merge operation, which can also (re-) create the project file (depending on configuration settings) while generating the other infrastructure files for the designated Help system.
Note: When you specify suffix C, I, or B for the -f argument, the input file must have extension .lst; see §45.3.3 Command-line argument input ....