The definition is not difficult. This is an addition, that is, in fact, the expansion of the capabilities of
a program on a computer, a browser (browser plug-in) or a specific Internet resource.
Why are they needed?
Why do we need a plugin? Is it really impossible to include all functions in a program in advance? No. Not one, even the most advanced developer,
is able to foresee all the wishes of users in advance. Therefore, they (as well as third parties) begin to write plugins over time
to meet the growing needs of users and at the same time improve, update the functionality of the program or site.
In addition, if you initially try to create truly advanced features in development, the program will simply be overloaded.
We, as users, get the basic version of the software, supplementing it with the help of plugins, which are simple enough to download and then install. This is what the plugin is for.
Some of them have a reminder that there is an update that should be installed. Such examples include the well-known Adobe Flash Player,
which indicates the possibility of updating with the release of each new version for one or another browser.