it was implemented as
SharedVariables which uses cookies in HTML; i posted a working example on the help page, there.
something that became an issue after implementation was
cross-site cookies which
AGKPlayer.js doesn't provide for while sites like itch.io run the games in an iframe (and the game itself is hosted on another site) but thanks to tboy,
the fix was easy for my
2020 lowrez jam game and continues to work without issue.
if you're self-hosting, you shouldn't have to make the change.
worth noting, as hosch mentioned in an
earlier post today, "general cookie size" is limited to 4096 bytes so, depending on what you're trying to do, this may present an issue.