We are in the same boat, we need to install Minemeld on 20.04 LTS but it requires libleveldb1v5 and I believe this package doesn't exist anymore so I cannot proceed further.
sudo apt install -o Dpkg::Options::="--force-overwrite" -y minemeld Reading package lists... Done Building dependency tree Reading state information... Done Some packages could not be installed. This may mean that you have requested an impossible situation or if you are using the unstable distribution that some required packages have not yet been created or been moved out of Incoming. The following information may help to resolve the situation:
The following packages have unmet dependencies: minemeld : Depends: libleveldb1v5 but it is not installable E: Unable to correct problems, you have held broken packages.
sudo apt-get install -y libleveldb1v5 Reading package lists... Done Building dependency tree Reading state information... Done Package libleveldb1v5 is not available, but is referred to by another package. This may mean that the package is missing, has been obsoleted, or is only available from another source
E: Package 'libleveldb1v5' has no installation candidate
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