I created a plugin with builder called Clients, with a table, model & controller for Companies. Afterward I updated a few things in the created files by hand, but I can't find what I might have done wrong. The plugin is still present in the system list, it shows up in the left pane in Builder, all its elements are accessible, and the Clients top menu link is there... However, when I click on it, the URL /qsp/clients/companies produces a 404 error.

Wracking my brain here... Any ideas?

Of course after hours of investigation, I find my own error two minutes after I post this topic. Well, for the benefit of anyone else seeing a 404 after hand-editing your plugin, make sure your controller class names are correct.