diff --git a/src/or/protover.c b/src/or/protover.c
index 8b61d96630..ae955296e6 100644
--- a/src/or/protover.c
+++ b/src/or/protover.c
@@ -34,6 +34,7 @@ static int protocol_list_contains(const smartlist_t *protos,
                                   protocol_type_t pr, uint32_t ver);
 
 /** Mapping between protocol type string and protocol type. */
+/// C_RUST_COUPLED: src/rust/protover/protover.rs `PROTOCOL_NAMES`
 static const struct {
   protocol_type_t protover_type;
   const char *name;
@@ -320,6 +321,7 @@ protocol_list_supports_protocol_or_later(const char *list,
 
 /** Return the canonical string containing the list of protocols
  * that we support. */
+/// C_RUST_COUPLED: src/rust/protover/protover.rs `SUPPORTED_PROTOCOLS`
 const char *
 protover_get_supported_protocols(void)
 {
@@ -403,6 +405,8 @@ encode_protocol_list(const smartlist_t *sl)
 
 /* We treat any protocol list with more than this many subprotocols in it
  * as a DoS attempt. */
+/// C_RUST_COUPLED: src/rust/protover/protover.rs
+///                 `MAX_PROTOCOLS_TO_EXPAND`
 static const int MAX_PROTOCOLS_TO_EXPAND = (1<<16);
 
 /** Voting helper: Given a list of proto_entry_t, return a newly allocated
@@ -729,6 +733,7 @@ protocol_list_contains(const smartlist_t *protos,
  * Note that this is only used to infer protocols for Tor versions that
  * can't declare their own.
  **/
+/// C_RUST_COUPLED: src/rust/protover/protover.rs `compute_for_old_tor`
 const char *
 protover_compute_for_old_tor(const char *version)
 {
diff --git a/src/or/protover.h b/src/or/protover.h
index 5884585ea6..a4dbc8bfc2 100644
--- a/src/or/protover.h
+++ b/src/or/protover.h
@@ -15,6 +15,8 @@
  * descriptors.  Authorities should use this to decide whether to
  * guess proto lines. */
 /* This is a guess. */
+/// C_RUST_COUPLED: src/rust/protover/protover.rs
+///                 `FIRST_TOR_VERSION_TO_ADVERTISE_PROTOCOLS`
 #define FIRST_TOR_VERSION_TO_ADVERTISE_PROTOCOLS "0.2.9.3-alpha"
 
 /** The protover version number that signifies HSDir support for HSv3 */
@@ -25,6 +27,8 @@
 #define PROTOVER_HS_RENDEZVOUS_POINT_V3 2
 
 /** List of recognized subprotocols. */
+/// C_RUST_COUPLED: src/rust/protover/ffi.rs `translate_to_rust`
+/// C_RUST_COUPLED: src/rust/protover/protover.rs `Proto`
 typedef enum protocol_type_t {
   PRT_LINK,
   PRT_LINKAUTH,