diff --git a/src/libstore/build-result.hh b/src/libstore/build-result.hh
index d39d23a76..cb6d19b8e 100644
--- a/src/libstore/build-result.hh
+++ b/src/libstore/build-result.hh
@@ -67,8 +67,8 @@ struct BuildResult
     /* The derivation we built or the store path we substituted. */
     DerivedPath path;
 
-    /* For derivations, the derivation path and the wanted outputs. */
-    std::optional<StorePath> drvPath;
+    /* For derivations, a mapping from the names of the wanted outputs
+       to actual paths. */
     DrvOutputs builtOutputs;
 
     /* The start/stop times of the build (or one of the rounds, if it
diff --git a/src/libstore/build/derivation-goal.cc b/src/libstore/build/derivation-goal.cc
index 325635e2e..afed9bf16 100644
--- a/src/libstore/build/derivation-goal.cc
+++ b/src/libstore/build/derivation-goal.cc
@@ -1324,7 +1324,6 @@ void DerivationGoal::done(
     DrvOutputs builtOutputs,
     std::optional<Error> ex)
 {
-    buildResult.drvPath = drvPath;
     buildResult.status = status;
     if (ex)
         // FIXME: strip: "error: "