diff --git a/README.md b/README.md
index 7ed532b..6bd95c8 100644
--- a/README.md
+++ b/README.md
@@ -1,2 +1,4 @@
 # ocaml-core
 
+Jane Street Capital's standard library overlay.
+
diff --git a/ocaml-core.spec b/ocaml-core.spec
new file mode 100644
index 0000000..95e7473
--- /dev/null
+++ b/ocaml-core.spec
@@ -0,0 +1,97 @@
+%define ocamlpck  core
+
+Name:          ocaml-core
+Version:       0.16.1
+Release:       1mamba
+Summary:       Jane Street Capital's standard library overlay
+Group:         System/Libraries/OCaml
+Vendor:        openmamba
+Distribution:  openmamba
+Packager:      Silvan Calarco <silvan.calarco@mambasoft.it>
+URL:           https://github.com/janestreet/core
+Source:        https://github.com/janestreet/core.git/v%{version}/core-%{version}.tar.bz2
+License:       MIT
+## AUTOBUILDREQ-BEGIN
+BuildRequires: glibc-devel
+BuildRequires: ocaml
+BuildRequires: ocaml-base-devel
+BuildRequires: ocaml-base_bigstring-devel
+BuildRequires: ocaml-base_quickcheck-devel
+BuildRequires: ocaml-bin_prot-devel
+BuildRequires: ocaml-fieldslib-devel
+BuildRequires: ocaml-int_repr-devel
+BuildRequires: ocaml-parsexp-devel
+BuildRequires: ocaml-ppx_assert-devel
+BuildRequires: ocaml-ppx_bench-devel
+BuildRequires: ocaml-ppx_compare-devel
+BuildRequires: ocaml-ppx_enumerate-devel
+BuildRequires: ocaml-ppx_expect-devel
+BuildRequires: ocaml-ppx_hash-devel
+BuildRequires: ocaml-ppx_here-devel
+BuildRequires: ocaml-ppx_inline_test-devel
+BuildRequires: ocaml-ppx_module_timer-devel
+BuildRequires: ocaml-ppx_sexp_conv-devel
+BuildRequires: ocaml-ppx_stable_witness-devel
+BuildRequires: ocaml-runtime
+BuildRequires: ocaml-sexplib-devel
+BuildRequires: ocaml-sexplib0-devel
+BuildRequires: ocaml-splittable_random-devel
+BuildRequires: ocaml-stdio-devel
+BuildRequires: ocaml-time_now-devel
+BuildRequires: ocaml-typerep-devel
+BuildRequires: ocaml-variantslib-devel
+## AUTOBUILDREQ-END
+BuildRequires: dune
+BuildRequires: ocaml
+BuildRequires: ocaml-findlib
+
+%description
+%{summary}.
+
+%package devel
+Group:         Development/Libraries/OCaml
+Summary:       Development files for %{name}
+Requires:      %{name} = %{?epoch:%epoch:}%{version}-%{release}
+
+%description devel
+This package contains libraries and signature files for developing applications that use %{name}.
+
+%debug_package
+
+%prep
+%setup -q -n core-%{version}
+
+%build
+dune build
+
+%install
+[ "%{buildroot}" != / ] && rm -rf "%{buildroot}"
+DESTDIR=%{buildroot} dune install --prefix "/usr" --libdir "%{_libdir}/ocaml"
+
+rm -rf %{buildroot}/usr/doc
+
+%clean
+[ "%{buildroot}" != / ] && rm -rf "%{buildroot}"
+
+%files
+%defattr(-,root,root)
+%dir %{_libdir}/ocaml/%{ocamlpck}
+%{_libdir}/ocaml/%{ocamlpck}/*
+%exclude %{_libdir}/ocaml/%{ocamlpck}/*.a
+%exclude %{_libdir}/ocaml/%{ocamlpck}/*.cmx
+%exclude %{_libdir}/ocaml/%{ocamlpck}/*.cmxa
+%exclude %{_libdir}/ocaml/%{ocamlpck}/*.mli
+%{_libdir}/ocaml/stublibs/*.so*
+%doc LICENSE*
+
+%files devel
+%defattr(-,root,root)
+%{_libdir}/ocaml/%{ocamlpck}/*.a
+%{_libdir}/ocaml/%{ocamlpck}/*.cmx
+%{_libdir}/ocaml/%{ocamlpck}/*.cmxa
+%{_libdir}/ocaml/%{ocamlpck}/*.mli
+%doc CHANGES* README.md
+
+%changelog
+* Sun Jul 09 2023 Silvan Calarco <silvan.calarco@mambasoft.it> 0.16.1-1mamba
+- package created using the webbuild interface