The environment file is parsed as <variable>=<value> and sets environment variables accordingly.
Note that the environment file is treated differently by openbox where it is simply sourced prior to running openbox.
It is recommended to specify keyboard settings here. See xkeyboard-config(7) for details.
For example, this sets keyboard layout to Swedish:
XCURSOR_THEME and XCURSOR_SIZE are also supported to set cursor theme and size respectively. The default size is 24.
Cursor themes can be found a the command below or similar:
find /usr/share/icons/ -type d -name "cursors"