new usb install. that directory sits now empty
Run apt update and see if it works. Meaning to look what sources it connects to, if it doesn’t fail.
If this fails, then ofc you have to create the file with the Trixie sources. There has to be a dummy file somewhere for you to copy.
I don’t really understand your post, you claim to have updated, but it’s a new usb install?
You will need some sort of source if you ever want to update. Trixie has support for the new format. see: https://ostechnix.com/migrate-to-deb822-format-debian-13-trixie/
You don’t need a /etc/apt/sources.list anymore, but you need something in /etc/apt/sources.list.d/ as per the above.
This helped
sudo apt modernize-sourcesI wish I’d known this was a thing before I spent 15 minutes searching the manpages and manually upgrading my sources…