How can I remove the working copy from a Mercurial clone?

Documentation at Mercurial wiki says following about bare repositories:

"Although this is a minor issue, Mercurial can obviously handle a bare repository; that is, a repository without a working copy. In Git you need a configuration option for that, whereas in Hg you only need to check out the null revision, like this:"

hg update null

The null revision is similar to the empty state you have when you have just done hg init. It is the parent of revision 0 (and the second parent of all non-merge revisions) and by updating back to it you again get an empty working copy.

The link may look ironic:

• https://www.mercurial-scm.org/wiki/GitConcepts