Jupyter file permission - PermissionError: [Errno 13] Permission denied: '/home/user/.cache/scikit-image/0.17.2/data/README.txt'

Hello,
when starting
nix-shell jupyter.nix

the auto-completion does not work, because
PermissionError: [Errno 13] Permission denied: '/home/user/.cache/scikit-image/0.17.2/data/README.txt'

but
! cat '/home/user/.cache/scikit-image/0.17.2/data/README.txt'
works

What are the permissions of that file? Who is owner?

nixos / the user account crashed (after home-manager rebuild [with nix-tree from nixpkgs master … ]) and there was only black-screen (after login) and a movable mouse …

now I’m setting up all new … then I can post the file infos