Is there a method to see changes to the Feature List over time?
Yes. If you have Backup files on this server, you may be able to make a comparison.
However, it would require System Backups that were running on your server, and are available.
First, you want to see your current Feature list. You can find it as flat files in the following location:
Example Feature List name: cptest1
Feature List Directory: /var/cpanel/features
# cat /var/cpanel/features/cptest1
Then, you would need to view the same file from an older System Backup.
Example System Backup location: /backup/2020-08-16/system/dirs/
File to extract from: _var_cpanel.tar.gz
You would extract the 'cptest1' file from _var_cpanel.tar.gz. If needed, reference the following article on how to retrieve it.
At this point, you can compare the current Feature List file to the extracted data to find differences.