src/vs/workbench/services/extensionManagement/browser/webExtensionsScannerService.ts/isGalleryExtensionInfo
function isGalleryExtensionInfo(obj: unknown): obj is GalleryExtensionInfo {
	const galleryExtensionInfo = obj as GalleryExtensionInfo | undefined;
	return typeof galleryExtensionInfo?.id === 'string'
		&& (galleryExtensionInfo.preRelease === undefined || typeof galleryExtensionInfo.preRelease === 'boolean')
		&& (galleryExtensionInfo.migrateStorageFrom === undefined || typeof galleryExtensionInfo.migrateStorageFrom === 'string');
}