Where can I download snap-sources_<version>_arm64.* package

Hi. SNAP documetnation mentions that to install snap sources one need to install snap-sources package. How can I get this package?

dpkg -i snap-sources__arm64.*

https://docs.nvidia.com/networking/display/bluefield3snap440/snap+deployment#src-2866990848_SNAPDeployment-InstallingSNAPSourcePackage