Some further indications for Ubuntu 22.04 beyond what Stephen said.

To get debug symbols and source, some setup is needed as in:

# Get debug symbols.
printf "deb http://ddebs.ubuntu.com %s main restricted universe multiverse\n" $(lsb_release -cs){,-updates,-security,-proposed} | \
 sudo tee -a /etc/apt/sources.list.d/ddebs.list
sudo apt install ubuntu-dbgsym-keyring
sudo apt update
sudo apt install coreutils-dbgsym

# Get source as per: https://askubuntu.com/questions/496549/error-you-must-put-some-source-uris-in-your-sources-list
# Produces directory "coreutils-8.32"
sudo cp /etc/apt/sources.list /etc/apt/sources.list~
sudo sed -Ei 's/^# deb-src /deb-src /'
/etc/apt/sources.list sudo apt-get update
apt source coreutils

Then, to get GDB to actually find the sources, you might need to either cd into the downloaded source, or play with stuff like:

set substitute-path . glibc-2.35

as mentioned at: https://askubuntu.com/questions/487222/how-to-install-debug-symbols-for-installed-packages/1434174#1434174