dbus-update-activation-environment: update environment variables that will be set for D-Bus
    session services

dbus-update-activation-environment [options] VAR[=VAL] [VAR2[=VAL2] ...]
    Add specified variables to D-Bus activation environment.
    If omitted, values are taken from current environment;
    variables not found in the environment are ignored.
dbus-update-activation-environment --all
    Add entire current environment to D-Bus activation
    environment.

Options:

--all
    Upload all environment variables.
--systemd
    Also update the 'systemd --user' environment
    if possible.
--verbose
    Talk about it.