src/vs/workbench/services/extensionManagement/browser/extensionEnablementService.ts/ExtensionsManager/onDidInstallExtensions
class ExtensionsManager:	private onDidInstallExtensions(extensions: IExtension[]): void {
		if (extensions.length) {
			this._extensions.push(...extensions);
			this._onDidChangeExtensions.fire({ added: extensions, removed: [] });
		}
	}