Files with ftx suffix are metadata files for specially formatted text files based on the Fielded Text schema.
FTX file extension - Fielded text meta file
What is ftx file? How to open ftx files?
File type specification:
File extension ftx is related to a special format called Fielded Text. It is a proposed standard which provides structure and schema definition to text files which contain tables of values (for example, CSV files).
The standard allows the format and structure of the data within the text file to be specified by a Meta file with the ftx file suffix. This Meta file can then be used to access the data in the file in manner similar to which data is accessed in a database.