The App Engine Blobstore was introduced in 2008 as a way to store large objects in your App Engine apps. Since then, Google Cloud has expanded and Cloud Storage has become the default way to store and serve arbitrary blobs. Beginning in 2014, we started recommending Cloud Storage instead of Blobstore.
As of June 1, 2019, the Blobstore UI is no longer available in the Google Cloud Console. The Blobstore API and associated client libraries continue to work, and legacy blob serving is not impacted.
If you need the functionality that the Blobstore UI previously provided, such as sorting, filtering, and deleting image URLs, you can run the open source Blobstore UI application. This is a separate App Engine module that runs alongside your existing application and surfaces the same functionality that the Blobstore UI previously provided. This application is not actively maintained by Google and does not have a Service Level Agreement (SLA).
If your blobs are stored in Cloud Storage and you don't need the functionality that the Blobstore UI previously provided, you can use the Cloud Storage object browser in the Cloud Console.
If your blobs are stored in legacy Blobstore, consider moving them to Cloud Storage with the App Engine Blobstore to Cloud Storage Migration Tool. Once you have migrated your blobs to Cloud Storage, you can still use the Blobstore API to store and serve your blobs, but you will also be able to manage the files with Google Cloud-supported tools such as the Google Cloud client libraries and gsutil.