src/vs/workbench/services/extensionResourceLoader/electron-sandbox/extensionResourceLoaderService.ts/ExtensionResourceLoaderService/readExtensionResource
class ExtensionResourceLoaderService:	async readExtensionResource(uri: URI): Promise<string> {
		if (this.isExtensionGalleryResource(uri)) {
			const headers = await this.getExtensionGalleryRequestHeaders();
			const requestContext = await this._requestService.request({ url: uri.toString(), headers }, CancellationToken.None);
			return (await asText(requestContext)) || '';
		}
		const result = await this._fileService.readFile(uri);
		return result.value.toString();
	}