diff --git a/swh/lister/nixguix/lister.py b/swh/lister/nixguix/lister.py
index 89bf4a84929386c8be583b765370ca104699f636..671e40d4a180e5bc37c156dea25ebc4b609a255c 100644
--- a/swh/lister/nixguix/lister.py
+++ b/swh/lister/nixguix/lister.py
@@ -262,9 +262,7 @@ def is_tarball(
             if location:  # It's not always present
                 logger.debug("Location: %s", location)
                 try:
-                    # FIXME: location is also returned as it's considered the true
-                    # origin, true enough?
-                    return _is_tarball(location), location
+                    return _is_tarball(location), url
                 except ArtifactWithoutExtension:
                     logger.warning(
                         "Still cannot detect extension through location <%s>...",
diff --git a/swh/lister/nixguix/tests/test_lister.py b/swh/lister/nixguix/tests/test_lister.py
index 180fe4fe54b2c6b7ab454e2fe044e4f15e8ffced..ab976f28c0ee028fa3af65cbb87645b9060d9796 100644
--- a/swh/lister/nixguix/tests/test_lister.py
+++ b/swh/lister/nixguix/tests/test_lister.py
@@ -189,7 +189,7 @@ def test_is_tarball_complex_with_location_result(
     is_tar, origin = is_tarball(urls, requests)
     assert is_tar == expected_result
     if is_tar:
-        assert origin == fallback_url
+        assert origin == url
 
 
 @pytest.mark.parametrize(