singularity moved out of lbl to its own company (the latest information is available at https://sylabs.io/singularity/). on a macbook, @Liza_Levitis suggests you can install docker. if you want to play with singularity locally, you can use Singularity desktop (which is somewhat limited on mac), or you can use the same container that’s available in the ABCD-Repronim Jupyterhub (see details at https://neurostars.org/t/using-abcd-repronim-jupyterhub-container-locally-via-docker).