      Promise.all([
                    fetch(mainCatalogUrl).then(response => response.json()),
                    fetch(communityCatalogUrl).then(response => response.json())
                ])
                    .then(([mainData, communityData]) => {
                        // Mark each dataset with its catalog source
                        mainCatalogDatasets = mainData.map(dataset => ({
                            ...dataset,
                            catalog_type: 'main'
                        }