When Netscape Navigator starts up, it checks for plug-in modules in the "plugins" subdirectory (Windows or OS/2) or "Plug-ins" folder (Macintosh) in the same folder or directory as the Navigator application. Plug-ins can be installed in the directory by manual installation, installation programs, or Navigator's assisted installation feature.
To view information about the currently installed plug-ins, the user can choose "About Plug-ins" from the Help menu (Window, OS/2 and UNIX) or Apple menu (Macintosh). Navigator will display a page listing all installed plug-ins and the MIME types they handle, as well as optional descriptive information supplied by the plug-in.
On Windows and OS/2, installed plug-ins are automatically configured to handle the MIME types that they support. If multiple plug-ins handle the same MIME type, the last plug-in loaded will handle the conflicting MIME type.
On Macintosh and UNIX, in Navigator 3.0, the user can flexibly configure which MIME types are handled by which plug-ins or helper applications, by using the "Helpers" tab of the General Preferences window. "Helpers" displays a list of all handled MIME types and whether the type is simply saved to disk or is handled by Navigator, a plug-in, or a helper application. The user can select any MIME type in the list and click the "Edit..." button to change how the MIME type is handled, including selecting a different plug-in to handle the type from a pop-up menu of all plug-ins that support that type.