It looks like that both the .xft and .xdp files are used for various forms in Adobe software, so perhaps users searching for xft to xdp conversion are looking exactly for that, to save forms between different formats.
We have not found anything about such export in particular, except for the fact that both files were supported in Adobe LiveCycle Designer and probably still are supported in successor product under Adobe Experience Cloud.
In case you struggle with this export or face particular issue regarding xft to xdp conversion, it might be best to reach out to Adobe support for help.
Updated: October 27, 2023