• List of default bridges are at https://gitlab.torproject.org/tpo/anti-censorship/team/-/wikis/Default-Bridges

Thank to

• Ranjeetsih, who wrote example of sys-tray with GTK at https://www.codeproject.com/Articles/27142/Minimize-to-tray-with-GTK
• Vivek Gite, who wrote tutorial of hook script for dhclient https://www.cyberciti.biz/faq/dhclient-etcresolvconf-hooks/