Yes, deb.torproject.org is also served through via an Onion Service: http://apow7mjfryruh65chtdydfmqfpj5btws7nbocgtaovhvezgccyjazpqd.onion/

Note: The symbol # refers to running the code as root. This means you should have access to a user account with system administration privileges, i.e. your user should be in the sudo group.

To use Apt over Tor, the apt transport needs to be installed:

   # apt install apt-transport-tor

Then you need to add the following entries to /etc/apt/sources.list or a new file in /etc/apt/sources.list.d/:

   # For the stable version.
   deb [signed-by=/usr/share/keyrings/tor-archive-keyring.gpg] tor://apow7mjfryruh65chtdydfmqfpj5btws7nbocgtaovhvezgccyjazpqd.onion/torproject.org <DISTRIBUTION> main

   # For the unstable version.
   deb [signed-by=/usr/share/keyrings/tor-archive-keyring.gpg] tor://apow7mjfryruh65chtdydfmqfpj5btws7nbocgtaovhvezgccyjazpqd.onion/torproject.org tor-nightly-main-<DISTRIBUTION> main

Replace <DISTRIBUTION> with your Operating System codename. Run lsb_release -c or cat /etc/debian_version to check the Operating System version.

Add the gpg key used to sign the packages by running the following command at your command prompt:

   # wget -qO- https://deb.torproject.org/torproject.org/A3C4F0F979CAA22CDBA8F512EE8CBC9E886DDD89.asc | gpg --dearmor | tee /usr/share/keyrings/tor-archive-keyring.gpg >/dev/null

Install tor and tor debian keyring

Now refresh your sources and try to install tor and tor debian keyring:

   # apt update
   # apt install tor deb.torproject.org-keyring