It’s a bug in your Dockerfile. You should drop the proposed line. See https://unix.stackexchange.com/q/484875/86440 for details.
** Changed in: fontconfig (Ubuntu) Status: New => Invalid -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1805820 Title: Dependency error installing fontconfig-dbgsym To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/fontconfig/+bug/1805820/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs