STAC is an organization of metadata for imagery and labels, making it easy to search for items that match spatial, temporal, or other criteria. At the root level of the STAC API is a list of collections of items. In the Radiant MLHub API, each collection contains items for either source imagery or labels for a dataset. These items are descriptions of source imagery or labels and links to download assets related to these items. Properties found in these item descriptions include spatial extent, temporal extent, band descriptions in the case of optical imagery, label types and label properties in the case of labels, and other information like DOIs and citation examples to reference.