No problem, now the question is how to check and remove it.
We just know the path is …devices/fyrtur_block-out_roller_blind.json but not realy precise, perhaps you can find the complete path with trying to save it again ?
You can try to set bad value to disable it.
And need to check if the changes are persistant or not, can help to know where the file is.
Here you have the complete procedure to edit DDF on the HA persistent folder How to add/edit a DDF on Home assistant using text editor?