It's not open-source or really polished for consumption. I did get permission to open-source it, but unfortunately didn't have the time to improve it to the point where it would be broadly useful.

In fact, now that https://tanstack.com/query/v4/docs/plugins/persistQueryClien... appears to be stable I'm thinking it might even be good to migrate to this (though it appears to require multiple queryclients if you want different cache parameters)