last-coding-system-specified

last-coding-system-specified is a variable defined in `mule-cmds.el'.
Its value is

nil

Documentation:
Most recent coding system explicitly specified by the user when asked.
This variable is set whenever Emacs asks the user which coding system
to use in order to write a file. If you set it to nil explicitly,
then call `write-region', then afterward this variable will be non-nil
only if the user was explicitly asked and specified a coding system.