What does the .sparsebundles extension indicate?

The .sparsebundle extension indicates a disk image format used by macOS that is created to store files in a way that optimizes storage. Specifically, it is a type of disk image that is divided into several smaller files (known as bands), which allows for more efficient usage of space compared to a standard disk image. This format is especially useful in networked environments, as it enables incremental backups.

When working with network storage, the sparse bundle format ensures that only the changes made since the last backup need to be transferred over the network, thus saving bandwidth and time. This makes it particularly suitable for backing up files on network drives, as it can help handle larger collections of data efficiently without requiring a full transfer of the image each time data is backed up or modified.