Add a few comments about the code.

1 files changed, 4 insertions, 0 deletions

diff --git a/kernel/environ.mli b/kernel/environ.mli
index 55df27a8b3..974e794c6b 100644
--- a/kernel/environ.mli
+++ b/kernel/environ.mli
@@ -69,7 +69,11 @@ type stratification = {
 type named_context_val = private {
   env_named_ctx : Constr.named_context;
   env_named_map : (Constr.named_declaration * lazy_val) Id.Map.t;
+  (** Identifier-indexed version of [env_named_ctx] *)
   env_named_var : Constr.t list;
+  (** List of identifiers in [env_named_ctx], in the same order, including
+      let-ins. This is not used in the kernel, but is critical to preserve
+      sharing of evar instances in the proof engine. *)
 }
 
 type rel_context_val = private {