Peculiar Pebble allows you to browse your Google Drive using a Google account for which you have valid credentials. It allows you to view the names, sizes, dates and owners of the files, as well as the folder structure. You can double-click the files to view them on your desktop. The files are opened using an embedded browser.
Peculiar Pebble clearly itself has access to your Google Drive, and the files inside. Any files that you double-click on will be downloaded into the embedded browser.
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 Google Drive, nor the name or credentials of your Google account, except that Google services themselves will be aware of which files and accounts you are accessing, and the actions you are taking.