I think they changed it recently, but all of the code you submit is embedded in ...

extraduder_ire 9 months ago | parent | context | favorite | on: Dogbolt Decompiler Explorer

I think they changed it recently, but all of the code you submit is embedded in the URL. (after an anchor) So, it's stored by google's link shortening service, but is resubmitted to the site every time you load it.