diff --git a/src/main/kotlin/com/beust/kobalt/api/IContributor.kt b/src/main/kotlin/com/beust/kobalt/api/IPluginActor.kt
similarity index 100%
rename from src/main/kotlin/com/beust/kobalt/api/IContributor.kt
rename to src/main/kotlin/com/beust/kobalt/api/IPluginActor.kt
diff --git a/src/main/kotlin/com/beust/kobalt/api/IRepoContributor.kt b/src/main/kotlin/com/beust/kobalt/api/IRepoContributor.kt
index 07937ac3..693a6777 100644
--- a/src/main/kotlin/com/beust/kobalt/api/IRepoContributor.kt
+++ b/src/main/kotlin/com/beust/kobalt/api/IRepoContributor.kt
@@ -6,6 +6,11 @@ import java.net.URI
  * Plugins that add their own repos.
  */
 interface IRepoContributor : IContributor {
+    /**
+     * Note that the project passed might be null because this contributor is called twice:
+     * before the build file gets parsed (so we don't have any projects yet) and after the
+     * build file has been parsed (then it gets called once for each project discovered).
+     */
     fun reposFor(project: Project?) : List<URI>
 }