doc/source/examples/alpine-autotools.rst: tweak intro to increase emphasis on base runtime
Increase emphasis on use of tarball containing minimal alpine image as the
base runtime of the project's sandbox.
diff --git a/doc/source/examples/alpine-autotools.rst b/doc/source/examples/alpine-autotools.rst
index e65b8c8..036de4b 100644
--- a/doc/source/examples/alpine-autotools.rst
+++ b/doc/source/examples/alpine-autotools.rst
@@ -2,8 +2,8 @@
Alpine Demo
===========
-This is a simple example using Buildstream to build a sandbox using a minimal
-`Alpine <https://alpinelinux.org/>`_ image. The example will use autotools to
+This is a simple example using Buildstream to build a sandbox from a tarball containing a minimal
+`Alpine <https://alpinelinux.org/>`_ image as the base runtime. The example will use autotools to
build the hello world example from `automake
<https://www.gnu.org/software/automake/manual/automake.html#Hello-World>`_
and install it in the sandbox.
