Unique IDs are a standard feature of the VST format that helps the hosts differentiate the plugins. While many hosts use the file name of the plugin as reference, Bidule and others use their unique IDs (which is the cleanest and most cross platform way to go). Sadly, most commercial hosts out there don't look at those, so many plugin developers don't enter a unique ID when they code their plugins. As a result, many plugins use the default names that were chosen by Steinberg in the SDK: "Gain","ADlE", "ADly" and "VxSy". We, and other host makers, have decided to deny the right for plugins using these IDs to work in Bidule. This is for reasons of code purity mostly, and to force developers to fix their plugins.
Same applies to Bidule, if a developer points out a fault in Bidule's hosting, we will gladly cooperate and fix our bugs. (Nobody writes perfect code:)
One of those features that are used more and more are the plugin's internal names, which can give a better description of the plugin to the user than its filename would. For example "Spectral Inverter Using Pvoc", instead of "si_up.dll" or "si_up.vst". If a plugin doesn't provide a name, Bidule will then revert to its filename.
Users wanting to use the filename only can change this option in the preferences menu.
As with Internal Names, the VST 2.0 standard also supports the plugins that export their company (vendor) name. Most newer plugins support this feature, but older ones seldom do. These automatically go into the "Unknown Vendor" category.
Users wanting to categorize plugins by their directory structure instead can do so by changing this option in the preferences.