This is the Debian/Ubuntu prepackaged version of firejail.

    Firejail is a sandbox program that reduces the risk of security breaches
    by restricting the running environment of untrusted applications using
    Linux namespaces. It currently implements hostname, filesystem, PID, IPC
    and networking stack isolation, and it runs on any recent Linux system. It
    includes a sandbox profile for Mozilla Firefox.

    Copyright (C) 2014-2019 Firejail Authors (see README file for more details)

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 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 General Public License for more details.

    You should have received a copy of the GNU General Public License along
    with this program; if not, write to the Free Software Foundation, Inc., 51
    Franklin St, Fifth Floor, Boston, MA 02110-1301, USA.

The complete text of the GNU General Public License can be found
in /usr/share/common-licenses/GPL-2.

Homepage: https://github.com/netblue30/firejail.