Upstream uses custom file as backend
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -4,7 +4,7 @@ requires = [
     "wheel",
     "setuptools_scm>=3.3.1,!=4.0.0",
 ]
-build-backend = "backend"
+build-backend = "setuptools.build_meta"
 backend-path = ["build_backend"]
 
 [tool.ruff.per-file-ignores]