src/vs/workbench/contrib/extensions/browser/extensionsWorkbenchService.ts/Extension/getManifest
class Extension:	async getManifest(token: CancellationToken): Promise<IExtensionManifest | null> {
		const local = this.getLocal();
		if (local) {
			return local.manifest;
		}

		if (this.gallery) {
			if (this.gallery.assets.manifest) {
				return this.galleryService.getManifest(this.gallery, token);
			}
			this.logService.error(nls.localize('Manifest is not found', "Manifest is not found"), this.identifier.id);
			return null;
		}

		return null;
	}