Well, it's actually about reverting the API change done in r4451 (after the introduction of WikiContext). There, the `render_macro` took a `formatter` first argument instead of a `req`. That's way more flexible, but was not well received, as it breaks compatibility with all the existing new-style macros (see #4568).
So the calling conventions for `render_macro` have been restored and a new method has been introduced for the plugins that want to take benefit from the 0.11 features (see #4139).
The relevant part of the API is:
{{{
#!python
class IWikiMacroProvider(Interface):
"""Extension point interface for components that provide Wiki macros."""
...
def render_macro(req, name, content):
"""Return the HTML output of the macro (deprecated)"""
def expand_macro(formatter, name, content):
"""Called by the formatter when rendering the parsed wiki text.
(since 0.11)
"""
}}}
