The INX file extension is associated with Adobe InDesign. INX format is used for exporting purposes to offer compatibility with previous versions of InDesign. INX file contains data in XML format, including pages, content, frames, etc.
The INX file extension is used by InstallShield software installer. INX file contains installation instructions. This file is not meant to be opened manually.
The INX file extension is used for extension descriptor by Inkscape, an open source vector graphics editor. INX file contains information of the extension and saved in an XML format.