Lifted from zope.app.rotterdam

• Create a new browser skin layer

from zope.publisher.interfaces.browser import IBrowserRequest
from zope.publisher.interfaces.browser import IDefaultBrowserLayer

class rotterdam(IBrowserRequest):
    """Layer for registering Rotterdam-specific macros."""

class Rotterdam(rotterdam, IDefaultBrowserLayer):
    """The ``Rotterdam`` skin.

    It is available via ``++skin++Rotterdam``.
    """

• Register the skin in configure.zcml

<interface
      interface="zope.app.rotterdam.Rotterdam"
      type="zope.publisher.interfaces.browser.IBrowserSkinType"
      name="Rotterdam"
      />

Declaring a resource and a page for the skin

 <browser:resource
      name="zope3.css"
      file="zope3.css"
      layer="zope.app.rotterdam.rotterdam" />

<browser:page
      for="*"
      name="standard_macros"
      permission="zope.View"
      class=".standardmacros.StandardMacros"
      layer="zope.app.rotterdam.rotterdam"
      allowed_interface="zope.interface.common.mapping.IItemMapping"
      />