.SKSE File Extension
File TypeSkyrim Script Extender Save File
File format categories include Binary, Text, XML, and Zip. The format of this file type has not been determined.
What is an SKSE file?
Save file created by Skyrim Script Extender (SKSE), a program used to extend scripts for The Elder Scrolls V: Skyrim game; contains data related to mods created by the SKSE program that cannot be saved in the ESS file; co-saved with .ESS files; should not be deleted otherwise the ESS file will be useless and any other SKSE program modifications may not work.
NOTE: To know which SKSE and ESS files are co-saved with each other, look for the same filename for both files.