\begin{frame}{Handling Library Upgrades}
  The goal:
  \begin{itemize}
  \item make the same fixes to \ext{libfoo} 2.0 as you did to 1.0
  \end{itemize}

  Vendor branches help you here:
  \begin{itemize}
  \item gives you clear distinction between
    \begin{itemize}
    \item changes made by the vendor
    \item your own changes
    \end{itemize}
  \end{itemize}
\end{frame}