For example in the phpmyadmin charm, we have an option to use the upstream version of phpmyadmin. During the demo Marco was playing with phpmyadmin and said that sometimes he prefers to use the latest upstream version instead of the package. Afterall, having an LTS of 5 years, at some point you might want to use that in case there’s no backport or PPA available.
So Marco just switched to it live.
juju set phpmyadmin use-upstream=true
Then he waited a few seconds for the magic charm to finish, hit refresh, and voila, fresh phpmyadmin. We then continued with the demo.
I suspect use-upstream style switches will be a common feature request for many charms.