Here for example, is \texttt{package/bridge/Makefile}:
\begin{Verbatim}[frame=single,numbers=left]
-# $Id: Makefile 5624 2006-11-23 00:29:07Z nbd $
include $(TOPDIR)/rules.mk
Which packages must be built/installed before this package. To reference a dependency defined in the
same Makefile, use \textit{<dependency name>}. If defined as an external package, use
\textit{+<dependency name>}. For a kernel version dependency use: \textit{@LINUX\_2\_<minor version>}
+ \item \texttt{BUILDONLY} (optional) \\
+ Set this option to 1 if you do NOT want your package to appear in menuconfig.
+ This is useful for packages which are only used as build dependencies.
\end{itemize}
\textbf{\texttt{Package/\textit{<name>}/conffiles} (optional):} \\
Compile templates.
\begin{Verbatim}[frame=single,numbers=left]
-# $Id: $
include $(TOPDIR)/rules.mk
Here for instance the Makefile for the I2C subsytem kernel modules :
\begin{Verbatim}[frame=single,numbers=left]
-# $Id $
I2CMENU:=I2C Bus