The latest versions of Chrome browser (starting with version 57) introduced disruptive change in the plugins support: the "Plugins" page (chrome://plugins) is now removed and replaced by "Components" page (chrome://components).
Following this change our Plugins Button extension is now checking your Chrome version and will open the new page on Chrome 57 and newer. For some time (until your particular copy of the browser gets the latest update) you will still see the old page, but at some point things will change.
The above change can be shown in pictures. Before Chrome 57 the Plugins button used to open the chrome://plugins page, which looked like that:
But starting with Chrome version 57 you will see the new (chrome://components) page:
The worst part of the change is that we cannot anymore disable/enable plugins on the new "components" page.
The only options I found so far are for some settings available for the Flash plugin and the PDF support.
You can now disable Flash in the Chrome "Settings -> Content" page (see below) and you can change the default PDF viewer (again in the "Settings" menu).
I've put a quick step-by-step tutorial if you are unsure how to access these: