I followed the instructions, as I understood them, and had an error.

I first executed

sudo apt install software-properties-common apt-transport-https
sudo apt update

Then:

mikes@studio1:~$ sudo apt-add-repository
https://cinelerra-gg.org/download/pkgs/ub20
Hit:1 http://us.archive.ubuntu.com/ubuntu focal InRelease
Hit:2 http://us.archive.ubuntu.com/ubuntu focal-updates InRelease
Hit:3 http://security.ubuntu.com/ubuntu focal-security InRelease
Hit:4 http://us.archive.ubuntu.com/ubuntu focal-backports InRelease
Ign:5 https://cinelerra-gg.org/download/pkgs/ub20 focal InRelease
Err:6 https://cinelerra-gg.org/download/pkgs/ub20 focal Release
   404  Not Found [IP: 104.27.142.18 443]
Reading package lists... Done
E: The repository 'https://cinelerra-gg.org/download/pkgs/ub20 focal
Release' does not have a Release file.
N: Updating from such a repository can't be done securely, and is
therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user
configuration details.

I've been able to compile by downloading source and then compiling
locally, but had to rebuild the system in order to solve a problem with
printing.

I'm still at the experimenting stage, so this is not a major problem.

Mike

--
Michael L. Squires, Ph.D., M.P.A.
546 North Park Ridge Road
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UN*X at home since 1985
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