diff --git a/docs/src/index.md b/docs/src/index.md
index 32aa2e2..2548300 100644
--- a/docs/src/index.md
+++ b/docs/src/index.md
@@ -23,6 +23,7 @@ run(`git config --global user.email "travis@c.i"`)
 run(`git config --global github.user "travis"`)
 using Pkg
 Pkg.activate(mktempdir())
+# This code gets run in docs/build/, so this path evaluates to the repo root.
 Pkg.add(PackageSpec(path=dirname(dirname(pwd()))))
 ```