To inject some data into the .fio header, the FioAdditions environment variable has to point to a Python file generating output.
p09/door/haso107d1.01 [4]: lsenv Name Value Type ---------------------------- -------------------------------------------------------------- ------ ... FioAdditions /online_dir/fioAdds.py str ...
The output of FioAdditions can be: list, dict, [list], [dict], [list, dict], [dict, list]. 'list' is always understood as list of strings.
Lists of strings are stored in the comment section of the header, dictionaries in the parameter section.