Where does 20.04 Software Updater keep log file?

Ubuntu 20.04.3 LTS current, maintained through Software Updater GUI application. Where does Software Update keep log files of the actual activity and results of each time it runs? If these are just the log files of child processes it forks/execs (e.g., apt or some incantation thereof), a complete list of locations and generic file names would be appreciated (e.g., foobar-log-xxxxx, muck-log-yyyyy, etc., where xxxxx, yyyyy, etc., are the specific run identifiers associated with each child process that actually is generating log files). There appears to be no answer to this subject on Ask Ubuntu that is anywhere near current.

Solution 1:

For files installed using the apt system, you can examine /var/log/apt/history.log - you may also find older log files in the directory /var/log/apt