Thanks. Now I got a little further, but ran into a new problem:
~/Downloads/torbrowser-launcher$ sudo apt install build-essential dh-python python3-all python3-stdeb python3-pyqt5 python3-gpg python3-requests python3-socks gnupg2 tor
Reading package lists... Done Building dependency tree Reading state information... Done E: Unable to locate package python3-gpg jcb@t4s:~/Downloads/torbrowser-launcher$ ./build_deb.sh
