Ginga is written so that most of the functionality of the program is achieved through the use of plugins. This modular approach allows a large degree of flexibility and customization, as well as making overall design and maintenance of the program simpler.
Plugins are divided into two types: global and local. A global plugin has a single instance shared by all channels, while a local plugin creates a unique instance for each channel. If you switch channels, a global plugin will respond to the change by updating itself, while a local plugin will remain unchanged if the channel is switched, because its operation is specific to a given channel. (Ginga’s concept of channels is discussed in Channels.)
An operation is the activation of a local plugin to perform some function. The plugin manager toolbar at the bottom of the center pane is the graphical way to start an operation.