This is add-on to replace the old safe_html from Portal Transform such that we can remove the CMFDefault dependencies and also this helps in removing the old safe_html transform and installing new safe_html transform on just inatalling the add-on.
Basically to get this add-on we have to go to the site setup and select add-ons and then install our new add-on named "experimental.safe_html_transform". After that when we click on the HTML Filtering from site setup we will see our new control panel instead of old safe_html control panel.
This add-on is required for two main reasons :- 1) It removes the CMFDefault dependencies from the Plone (From HTML Filtering) 2) It is quite faster transform then the earlier one as it uses lxml for filtering HTML
Works same as the old safe_html but more accurate and fast. Also when we install this add-on then the old safe_html transform is unregistered and our new transform is registered just on installing the add-on. Quite Cool, right ? :P