Mm-hm. I agree with this whole-heartedly. I performed this "hack" with pemasu's Raring 3992, and it brought the repos back online with no issues.
Canonical still keep every single bit of software they've ever produced for Ubuntu, dating all the way back to 2004. This includes all the various distro-release package listings, which is what the Puppy Package Manager uses, and reads from. These in turn will permit whatever 'buntu-based Pup you're using to access the appropriate parts of the main 'pool' archive & retrieve the selected, date-correct items for it to use.
@stuvxz :-
Ya gotta bear the following in mind. Precise-light is based on Ubuntu 12.04 LTS "Precise Pangolin". This was released in April 2012, and was the first LTS release to gain the full 5 years support package, OK? Officially, this OS hit EOL in April 2017.
Now, at EOL Ubuntu move the repos for any given release into the "old-releases" package archive pool. In the case of very popular versions (and "Precise" was very definitely one of these), the repos tend to stay in the normal location for rather longer. I remember, for sure, that the Precise repos were still functioning as of November 2019, shortly before the pandemic began to develop. This was almost unheard of, but it just goes to show that a great many people - including quite a number of enterprise users who had moved their office systems across to Linux during this time-frame - were STILL using it.
I would have been extremely surprised if things had continued in that vein for very much longer.
Follow 6502coder's link, and have a look. It involves locating, and opening, a normally unaccessed file in /root. It looks daunting, when you first open the file with your favourite text-editor, but in fact it only involves editing 3 or 4 lines & editing a small portion of the URL for each of them.
When you're done, you've double-checked, are happy with the result, and have 'Saved'/closed the file, don't forget to update the repos again so that they're reading from the new location.....
Let us know if you're successful, please? Thanks.
Mike. 
