The Ubuntu font and a fresh look at open font licensing

"... modified versions that are not 'Substantially Changed' must be renamed to append the derivative name to the original name.... The UFL further specifies that the license does not grant any rights to trademarks associated with the original font."

So... if you make a minor change to the font you have to include the original (trademarked) name in the name of the new font, but you aren't granted any rights to use said trademark? How does that work, exactly? No minor forks permitted without a separate trademark license?