diff --git a/include/crm/common/rules.h b/include/crm/common/rules.h
index d6d408a8f5..751957ede1 100644
--- a/include/crm/common/rules.h
+++ b/include/crm/common/rules.h
@@ -1,44 +1,47 @@
 /*
  * Copyright 2004-2023 the Pacemaker project contributors
  *
  * The version control history for this file may have further details.
  *
  * This source code is licensed under the GNU Lesser General Public License
  * version 2.1 or later (LGPLv2.1+) WITHOUT ANY WARRANTY.
  */
 
 #ifndef PCMK__CRM_COMMON_RULES__H
 #  define PCMK__CRM_COMMON_RULES__H
 
 #ifdef __cplusplus
 extern "C" {
 #endif
 
 /*!
  * \file
  * \brief Scheduler API for rules
  * \ingroup core
  */
 
 /* Allowed subexpressions of a rule
  * @COMPAT This should be made internal at an API compatibility break
  */
+//!@{
+//! \deprecated For Pacemaker use only
 enum expression_type {
     not_expr        = 0,
     nested_rule     = 1,
     attr_expr       = 2,
     loc_expr        = 3,
     role_expr       = 4,
     time_expr       = 5,
 #if !defined(PCMK_ALLOW_DEPRECATED) || (PCMK_ALLOW_DEPRECATED == 1)
     version_expr    = 6,
 #endif
     rsc_expr        = 7,
     op_expr         = 8,
 };
+//!@}
 
 #ifdef __cplusplus
 }
 #endif
 
 #endif // PCMK__CRM_COMMON_RULES__H