[Sony Xperia X Compact ROMs, Kernels, Recoveries, &] realtuxen:
those dirs gets restored if you modify or add any files when you restart flashtool, and they get updated all the time from the server. I found old remains of a install that has a default.fsc, 34.2.A.0.266.fsc, and a properties file. of cause as said you can not copy these files to devices when flashtool starts they get cleared they are also long gone, I do not think you should mess with these files.

Anyway I also get the same 34.fsc and a properties file in devices with flashtool 0.9.22.3 (same as with new version, as they are pulled from same server) and it does not prompt me anymore but the dk.ta inside the ftf seems to get written just as if I answered no.

28/028/2017 20:28:57 - INFO - Selected Bundle for Sony Xperia X Compact(F5321). FW release : 1.0. Customization : DeviceKey

28/028/2017 20:28:57 - INFO - Preparing files for flashing

28/028/2017 20:28:57 - INFO - Please connect your device into flashmode.

28/028/2017 20:28:57 - INFO - Start Flashing

28/028/2017 20:28:57 - INFO - No loader in the bundle. Searching for one

28/028/2017 20:28:57 - INFO - No matching loader found

28/028/2017 20:28:57 - WARN - No loader found or set manually. Skipping loader

28/028/2017 20:28:57 - INFO - Max packet size set to 512K

28/028/2017 20:28:57 - INFO - USB buffer size set to 512K

28/028/2017 20:28:57 - INFO - No flash script found. Using 0.9.18 flash engine

28/028/2017 20:28:57 - INFO - Opening TA partition 2

28/028/2017 20:28:57 - INFO - Writing TA unit 00002774. Value : 01

28/028/2017 20:28:57 - INFO - Closing TA partition

28/028/2017 20:28:57 - INFO - Opening TA partition 2

28/028/2017 20:28:57 - INFO - Closing TA partition

28/028/2017 20:28:57 - INFO - Opening TA partition 2

28/028/2017 20:28:57 - INFO - Closing TA partition

28/028/2017 20:28:57 - INFO - Opening TA partition 2

28/028/2017 20:28:57 - INFO - Closing TA partition

28/028/2017 20:28:57 - INFO - Opening TA partition 2

28/028/2017 20:28:57 - INFO - Flashing DK.ta to partition 2

28/028/2017 20:28:57 - INFO - Writing TA unit 000007EC. Value : C0 02 00 02 44 4B 00 00 00 00 00 00 00 00 00 00 7F B5 B7 03 08 9C C5 E5 7A 11 FD D8 8F 2D 53 F5

28/028/2017 20:28:57 - INFO - Closing TA partition

]28/028/2017 20:28:57 - INFO - Opening TA partition 2

28/028/2017 20:28:57 - INFO - Closing TA partition

28/028/2017 20:28:57 - INFO - Opening TA partition 2

28/028/2017 20:28:57 - INFO - Writing TA unit 00002725. Value : 32 30 31 37 2D 30 31 2D 32 38 20 32 30 3A 32 38 3A 35 37 00

28/028/2017 20:28:58 - INFO - Writing TA unit 00002774. Value : 00

28/028/2017 20:28:58 - INFO - Closing TA partition

28/028/2017 20:28:58 - INFO - Ending flash session

28/028/2017 20:28:58 - INFO - Flashing finished.

28/028/2017 20:28:58 - INFO - Please unplug and start your phone

28/028/2017 20:28:58 - INFO - For flashtool, Unknown Sources and Debugging must be checked in phone settings

The number in red are my device key ie. the contents of DK.ta (you can unzip ftf files with unzip, WinRAR, etc)

This also strangely matches your post #107 (except the dk value ofc), and if you notice it goes on with its thing when no flash script found and writes using 0.9.18 flash engine. But as you say your fido_keys are not provisioned. Strange. You could try match your numbers up with whatever you did in post #107, or replicate the process. perhaps you can narrow something in, I dunno. It was just something I noticed.

I can not get it to work with any later flashtool versions, i tried kianush idea with mydevices to leave no stone unturned only to get the same no fsc present.