- **Added:**
  Facts about ``Permutation``:

  - structure: ``Permutation_refl'``, ``Permutation_morph_transp``
  - compatibilities: ``Permutation_app_rot``, ``Permutation_app_swap_app``, ``Permutation_app_middle``, ``Permutation_middle2``, ``Permutation_elt``, ``Permutation_Forall``, ``Permutation_Exists``, ``Permutation_Forall2``, ``Permutation_flat_map``, ``Permutation_list_sum``, ``Permutation_list_max``
  - inversions: ``Permutation_app_inv_m``, ``Permutation_vs_elt_inv``, ``Permutation_vs_cons_inv``, ``Permutation_vs_cons_cons_inv``, ``Permutation_map_inv``, ``Permutation_image``, ``Permutation_elt_map_inv``
  - length-preserving definition by means of transpositions ``Permutation_transp`` with associated properties: ``Permutation_transp_sym``, ``Permutation_transp_equiv``, ``Permutation_transp_cons``, ``Permutation_Permutation_transp``, ``Permutation_ind_transp``

  (`#11946 <https://github.com/coq/coq/pull/11946>`_,
  by Olivier Laurent).