src/Plugin/PluginManager.php
public function initPluginInstalled() {
        try {
            foreach ($this->pluginPaths as $path) {
                //Get the installed plugins
                $newPluginInstalled = $this->pluginLocator->getInstalledPlugins($this->autoloader->getURLBase().$path);
                $listOfPluginsInstalled = $this->createPluginInstances($newPluginInstalled, true);
                foreach ($listOfPluginsInstalled as $newPlugin) {
                    $this->pluginList[] = $newPlugin['plugin'];
                }
            }
            return $this->pluginList;
        } catch (Exception $e) {
            throw new PluginException('Plugin Manager: Can not init all plugins. '
                    . 'Please find attach the error from the '
                    . 'initialization:'. $e->getMessage());
        }
    }
public function initPluginInstalled() {
        try {
            foreach ($this->pluginPaths as $path) {
                //Get the installed plugins
                $newPluginInstalled = $this->pluginLocator->getInstalledPlugins($this->autoloader->getURLBase().$path);
                $listOfPluginsInstalled = $this->createPluginInstances($newPluginInstalled, true);
                foreach ($listOfPluginsInstalled as $newPlugin) {
                    $this->pluginList[] = $newPlugin['plugin'];
                }
            }
            return $this->pluginList;
        } catch (Exception $e) {
            throw new PluginException('Plugin Manager: Can not init all plugins. '
                    . 'Please find attach the error from the '
                    . 'initialization:'. $e->getMessage());
        }
    }
Get the list of plugins installed and init them.

@return false | array(PluginInterface)
@throws PluginException