To specify a file name for the index:
[Index] ; IDXFile = base name to use for output file, with suffix IDX IDXFile = mapnameIDX ; IDXSuffix = suffix for the base file name, default IDX IDXSuffix = IDX ; IndexFileSuffix = suffix to add to map name for index file ; if no IDXFile name (deprecated) IndexFileSuffix = IDX.htm
If you specify a value for IDXFile, IDXSuffix is ignored. See §14.2 Naming generated HTML list and index files.
For IndexFileSuffix, you must include the file extension as well as a suffix to add to the base map name. The default suffix is IDX.htm. Use of IndexFileSuffix is deprecated. If you provide a value for IDXFile, DITA2Go ignores IndexFileSuffix.
By default, DITA2Go writes the index title as a heading at the top of the index page. To omit this heading:
[Index] ; UseIndexHeading = Yes (default, put a title on the index) or No. UseIndexHeading = No
When UseIndexHeading=Yes, the title appears at the top of the index page. To provide a different kind of title of your own devising, set UseIndexHeading=No and use [Inserts] keyword IndexTop to specify code or a macro to produce a title; see §14.7.3.5 Customizing and linking to the index file.
To specify a prefix for index-link anchor names:
[Index] ; IndexNumPrefix = prefix to use for <a name=...>s for index items IndexNumPrefix = ixnum
The default value of IndexNumPrefix is ixnum. Unless you need to match an external convention, just use the default value. DITA2Go uses the resulting IDs to provide jumps from see and see-also entries to their target index entries.