I was recently editing the Wikipedia page for Google Bookmarks (2005-2021). I wanted to add a logo to the page, but I was having a lot of trouble finding a high-quality copy of the logo anywhere. Eventually I figured out that Google's old URL scheme for product logos was very guessable, and they had never taken it down: https://www.google.com/intl/en-US/images/logos/bookmarks_log...
They'll probably never stop serving those old URLs because who KNOWS where they might still be in use. One of surely a million examples of weird little legacy things Google is stuck with.
That's good! Cool URLs never die. I thought they would be able to do a more effective search of their codebase to find references to their old logo in their own code.
I'm sure they could, but to what end? It'd be a bunch of work to find them all, and they could never really be sure they didn't miss one. Meanwhile the cost of just serving that old logo forever is basically nothing.
I tried to guess what it might be ... I went to check moon.google.com, one of the older apps/jokes that I can recall still running. It seems that they got someone to update moon.google.com with a more recent look and feel, and dozens of moons instead of just the one.
Indeed, I recently ran into a Google page that served up the old (~2013) Catull logo.