How to know if a site is using Multisite?

Is it possible to determine whether a WordPress site is using Multisite feature from the browser or some other tool?

Here’s a few ways to spot it, but it depends on what access you have or how the site is set up, and won’t spot that it’s a multisite in all cases.

If you have a login / access to the admin site, there’s two ways I can see

1. on the admin site the body tag will have class “multisite”
   (I think this is the only way here that you can say definitively ‘not a multisite’ if this class is missing)
2. if you generate a password reset email then it will include the site name which may be different to the blog name (but equally may not, so you can’t definitely infer not a multisite)

If you don’t, and if the sign-ups are enabled

• if the sign-up link redirects to a different domain then this is a multisite and not the primary site in the multisite.
  (It may also be a multisite but this is the primary site so there’s no redirect.)