src/vs/platform/extensionManagement/common/extensionGalleryService.ts/AbstractExtensionGalleryService/getManifestFromRawExtensionVersion
class AbstractExtensionGalleryService:	private async getManifestFromRawExtensionVersion(rawExtensionVersion: IRawGalleryExtensionVersion, token: CancellationToken): Promise<IExtensionManifest | null> {
		const manifestAsset = getVersionAsset(rawExtensionVersion, AssetType.Manifest);
		if (!manifestAsset) {
			throw new Error('Manifest was not found');
		}
		const headers = { 'Accept-Encoding': 'gzip' };
		const context = await this.getAsset(manifestAsset, { headers });
		return await asJson<IExtensionManifest>(context);
	}