/etc/NetworkManager/dispatcher.d/10-freedombox-batman is in plinth 0.13.1+ds-1.
This file is owned by root:root, with mode 0o755.
The actual contents of the file can be viewed below.
| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 | #!/bin/bash
#
# This file is part of Plinth.
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as
# published by the Free Software Foundation, either version 3 of the
# License, or (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU Affero General Public License for more details.
#
# You should have received a copy of the GNU Affero General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.
#
set -e  # Exit with code on error
IFACE="$1"
ACTION="$2"
if [[ "$CONNECTION_ID" != *"BATMAN"* ]]; then
    exit 0
fi
case ${ACTION} in
    up)
        logger "Setting up B.A.T.M.A.N. Advanced on interface $IFACE"
        ip link set mtu 1560 dev ${IFACE}
        modprobe batman-adv
        echo "bat0" > /sys/class/net/${IFACE}/batman_adv/mesh_iface
        ip link set up dev bat0
        ;;
    down)
        logger "Clearing B.A.T.M.A.N. Advanced on interface $IFACE"
        ip link set down dev bat0
        echo "none" > /sys/class/net/${IFACE}/batman_adv/mesh_iface
        ip link set mtu 1500 dev ${IFACE}
        ;;
    *)
        ;;
esac
 |