Default setting for ezwebin/ezwebin/ezdemo in 4.x is that:
if you login to siteaccess : ezwebin_site

• you are also logged in to siteaccess :eng
• you are not logged in to siteaccess : ezwebin_site_admin
• This is controlled by ini setting : SessionNamePerSiteAccess=enabled/diabled
  In other words, front end siteaccesses share session, while admin siteaccesses do not....

In ezp5, we have a setting in app/config/config.yml:
session:
name: "eZSESSID"

1. name: "eZSESSID {siteaccess_hash}

   "

In other words we don't support the ezp4.x schema... Either no siteaccesses share session, or all siteaccesses share the same session