[GTALUG] "free" physical objects

Hi everyone, a few years back(before COVID) I participated in a very interesting GTALUG meeting. One of the participants talked about some "free" objects/artifacts that are circulating in our world and people can keep them for certain time. Each object has an id and the temporary "guardian" informs a portal that they have it in their possession using this id. Does anyone remembers this conversation? Does anyone know this project? Thank you for your time stopping by my message. Best, -- Vasileios Papadiamantopoulos, PhD Arch