They don't really hurt anything
To
purge obsolete export templates, you will lose all settings for the export type Post 2
https://www.mobileread.com/forums/sho...38&postcount=2listed the different kinds
All the user templates are in the calibre configuration folder:
save_to_disk.py
others (sample)
device_drivers_FOLDER_DEVICE_FOR_CONFIG.py
device_drivers_HANLINV5.py
Deleting the specific file will reload the Default the next time the configure device setting option is used