For a few minutes today the package "fs" was unpublished from the registry in response to a user report that it was spam. It has been restored. This was a human error on my (@seldo's) part; I failed to properly follow our written internal process for checking if an unpublish is safe. My apologies to the users and builds we disrupted.
More detail: the "fs" package is a non-functional package. It simply logs the word "I am fs" and exits. There is no reason it should be included in any modules. However, something like 1000 packages *do* mistakenly depend on "fs", probably because they were trying to use a built-in node module called "fs". Given this, we should have deprecated the module instead of unpublishing it, and this is what our existing process says we should do.
If any of your modules are depending on "fs", you can safely remove it from your dependencies, and you should. But if you don't, things will continue to work indefinitely.