Mmbb.7z -

: The .7z extension indicates that the dataset is compressed using the 7-Zip format to handle the massive file sizes typical of high-resolution neuroimaging. Why you might see "Proper":

: The paper describes the acquisition, preprocessing, and validation of the brain imaging data to ensure it is "properly" formatted for machine learning and neuroscience research. MMBB.7z

(or the corresponding journal version published in Scientific Data or similar venues depending on the version). Key Details of the Paper: MMBB.7z