We do not have furo packaged and it is not needed to run tests.

--- elastic_transport-8.17.1/setup.py.orig
+++ elastic_transport-8.17.1/setup.py
@@ -71,7 +71,6 @@
             "orjson",
             # Override Read the Docs default (sphinx<2)
             "sphinx>2",
-            "furo",
             "sphinx-autodoc-typehints",
         ],
     },