A plug-in (from the English plug-in) is an independent software module that can be connected to an application to expand its capabilities or make special use of existing ones. Most often plugins are presented as shared libraries.
How plugins work is as follows. The application they target provides them with services to use them. These services include such features as registering a plugin in the program, as well as a protocol that allows you to exchange information with other plugins. As a rule, plugins are rarely used without the provided services, since they are dependent on them. In turn, the program allows users to add, remove and update plugins without any changes to the application itself. Among the applications that provide the ability to create plugins for them can be programs for editing images, audio and video, Internet browsers, multimedia players, office applications. etc. You can also mark plugins for content management systems (CMS), for example, for Wordpress or Joomla. Installation of plugins can be done in several ways. For example, Internet browsers allow you to install plugins by providing a custom interface for this. In a special tab, a repository with plugins opens, which are installed by clicking on the corresponding buttons. For some programs, plug-ins are installed by copying the corresponding files into specially designated program folders. When the application is launched, these directories are checked for the presence of plugin files and, if they exist, are connected to the application. For image editing programs, plugins can add functionality for color correction, some kind of deformation, watermarking, etc. Quite often, plugins allow programs to work with those types of files that are not initially supported. In sound editors, plugins are used to create certain effects, to distort sound, change its characteristics. Particularly popular are plugins for web browsers that are able to block ads and pop-up windows, provide statistical information about the pages viewed, download video files, etc.
