it's not worth this turning into compatibility baggage just so that we can parse plugin_list.yml, especially when we have new ways to handle data parsing coming in the pipeline.
For something as small as plugin_list.yml, it's easier (and in this case better too) to just validate it manually (respect/validation was anyway too strict considering it's YAML we're dealing with).
this fixes a few crashes that could appear from invalid plugin_list.yml setups, which was the reason #3228 was opened to begin with. Respect also has nicer error messages, as long as you don't use the static API :)
