/usr/lib/ubuntu-mate/ubuntu-mate-tilda is in ubuntu-mate-default-settings 16.04.5.
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  | #!/usr/bin/env bash
function overlay_file() {
    local SYSTEM_FILE="/usr/share/ubuntu-mate/settings-overlay/${1}"
    local USER_FILE="${HOME}/.${1}"
    local USER_DIR=$(dirname "${USER_FILE}")
    # If the file doesn't exist or is zero-bytes then overlay the
    # configuration.
    if [ ! -f "${USER_FILE}" ] || [ ! -s "${USER_FILE}" ]; then
        mkdir -p "${USER_DIR}"
        cp "${SYSTEM_FILE}" "${USER_FILE}"
    fi
}
overlay_file config/tilda/config_0
tilda &
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