[philclifford]

This is the real solution for #767

It needs checking/implementing for these too:

grep -L CODENAMES_SUPPORTED $(grep -l  UPSTREAM_CODENAME  $(grep -l APT 01-main/packages/*))
01-main/packages/azure-cli
01-main/packages/docker-ce
01-main/packages/dropbox
01-main/packages/insync
01-main/packages/jellyfin
01-main/packages/nomad
01-main/packages/tailscale
01-main/packages/tarsnap
01-main/packages/terraform
01-main/packages/ungoogled-chromium
01-main/packages/waydroid
01-main/packages/weechat

Update: all above checked and those that can be seen to be restricted to some releases (azure-cli) or need mapping (waydroid) have been addressed in #770