Partially related question: There was an article about the implementation of supervisors and you can’t use the “let is crash philosophy” in the whole erlang/be

Partially related question: There was an article about the implementation of supervisors and you can’t use the “let is crash philosophy” in the whole erlang/beam stack but there is a small (loc) implementation in C which has to be proven safely in order for the “let it crash philosophy” to work. I don’t know if this was the definition and implementation of a supervisor itself or a process itself. Does anybody know what I mean and which article I am referring to? If so, I would be glad if you could post a link to the article