diff --git a/build-aux/test-env.in b/build-aux/test-env.in
index b1470bb953..6b0f8daa87 100644
--- a/build-aux/test-env.in
+++ b/build-aux/test-env.in
@@ -53,7 +53,6 @@ then
     NIX_LOCALSTATE_DIR="@GUIX_TEST_ROOT@/var"
     GUIX_LOG_DIRECTORY="@GUIX_TEST_ROOT@/var/log/guix"
     GUIX_DATABASE_DIRECTORY="@GUIX_TEST_ROOT@/db"
-    NIX_ROOT_FINDER="@abs_top_builddir@/nix/scripts/list-runtime-roots"
 
     # Choose a PID-dependent name to allow for parallel builds.  Note
     # that the directory name must be chosen so that the socket's file
@@ -98,7 +97,7 @@ then
 
     export NIX_IGNORE_SYMLINK_STORE NIX_STORE_DIR		\
 	NIX_LOCALSTATE_DIR GUIX_LOG_DIRECTORY GUIX_STATE_DIRECTORY GUIX_DATABASE_DIRECTORY	\
-	NIX_ROOT_FINDER GUIX_BINARY_SUBSTITUTE_URL		\
+	GUIX_BINARY_SUBSTITUTE_URL				\
         GUIX_ALLOW_UNAUTHENTICATED_SUBSTITUTES			\
         GUIX_CONFIGURATION_DIRECTORY XDG_CACHE_HOME NIXPKGS
 
diff --git a/nix/libstore/gc.cc b/nix/libstore/gc.cc
index c466996668..fe152da015 100644
--- a/nix/libstore/gc.cc
+++ b/nix/libstore/gc.cc
@@ -620,10 +620,9 @@ void LocalStore::collectGarbage(const GCOptions & options, GCResults & results)
 
     foreach (Roots::iterator, i, rootMap) state.roots.insert(i->second);
 
-    /* Add additional roots returned by the program specified by the
-       NIX_ROOT_FINDER environment variable.  This is typically used
-       to add running programs to the set of roots (to prevent them
-       from being garbage collected). */
+    /* Add additional roots returned by 'guix gc --list-busy'.  This is
+       typically used to add running programs to the set of roots (to prevent
+       them from being garbage collected). */
     if (!options.ignoreLiveness)
         addAdditionalRoots(*this, state.roots);