In /opt directory you have 2 PBXware related directories:
httpdpbxwarehttpd - Setup Wizard/Licenser is a kind of controller for pbxware chroot. httpd is not a chroot and is the only part of the system which requires root privileges. In httpd/bin you have an application named mini_httpd which will bind to port '81' by default.
pbxware - Consist of a chroot, with no root privileges, and several important processes -
sitemanager - it is a part of the pbxware chroot and all the relevant files are located in /opt/pbxware/pw/guidirectory.