Peculiar Pebble allows you to browse the buckets for one or more Google Cloud accounts to which you have valid credentials. It allows you to view the files in the buckets, the folder structure. You can download the files, to your local computer, and view the contents. You can open the files by double-clicking them, which causes the file to be first downloaded to a local temporary directory. You can drag files from the bucket to your local computer, and you can drag files from your local computer to the bucket. You can also delete files from the bucket. You can create and delete folders in the bucket.
Peculiar Pebble clearly itself has access to the buckets, and the files in the buckets. Any files that you double-click on will be stored locally inside a temporary directory inside the application's container. The files will not be removed, in this version of the app.
Peculiar Pebble does not transmit any information to myself, or others, about the files you access, nor their contents, nor the contents nor structures of the buckets, nor the names of the buckets, except that the Google Cloud services themselves will be aware of which buckets you are accessing, and the files you are accessing, and the actions you are taking.