diff --git a/src/sl/saveload.cpp b/src/sl/saveload.cpp
index 7f85345a47..5f26856071 100644
--- a/src/sl/saveload.cpp
+++ b/src/sl/saveload.cpp
@@ -2277,7 +2277,7 @@ std::vector<SaveLoad> SlTableHeader(const NamedSaveLoadTable &slt, TableHeaderSp
 					}
 
 					/* We don't know this field, so read to nothing. */
-					saveloads.push_back({ true, saveload_type, ((VarType)type & SLE_FILE_TYPE_MASK) | SLE_VAR_NULL, 1, SL_MIN_VERSION, SL_MAX_VERSION, nullptr, 0, SlXvFeatureTest() });
+					saveloads.push_back({ true, saveload_type, ((VarType)type & SLE_FILE_TYPE_MASK) | SLE_VAR_NULL, 1, SL_MIN_VERSION, SL_MAX_VERSION, SLTAG_TABLE_UNKNOWN, nullptr, 0, SlXvFeatureTest() });
 					continue;
 				}
 
diff --git a/src/sl/saveload.h b/src/sl/saveload.h
index cb344d7df8..ce842a2043 100644
--- a/src/sl/saveload.h
+++ b/src/sl/saveload.h
@@ -501,7 +501,7 @@ inline constexpr void *SlVarWrapper(void* ptr)
  * @param extver   SlXvFeatureTest to test (along with from and to) which savegames have the field
  * @note In general, it is better to use one of the SLE_* macros below.
  */
-#define SLE_GENERAL_X(cmd, base, variable, type, length, from, to, extver) SaveLoad {false, cmd, type, length, from, to, SlVarWrapper<decltype(base::variable), cmd, type, length>((void*)cpp_offsetof(base, variable)), sizeof(base::variable), extver}
+#define SLE_GENERAL_X(cmd, base, variable, type, length, from, to, extver) SaveLoad {false, cmd, type, length, from, to, SLTAG_DEFAULT, SlVarWrapper<decltype(base::variable), cmd, type, length>((void*)cpp_offsetof(base, variable)), sizeof(base::variable), extver}
 #define SLE_GENERAL(cmd, base, variable, type, length, from, to) SLE_GENERAL_X(cmd, base, variable, type, length, from, to, SlXvFeatureTest())
 
 /**
@@ -719,8 +719,8 @@ inline constexpr void *SlVarWrapper(void* ptr)
 /** Translate values ingame to different values in the savegame and vv. */
 #define SLE_WRITEBYTE(base, variable) SLE_GENERAL(SL_WRITEBYTE, base, variable, 0, 0, SL_MIN_VERSION, SL_MAX_VERSION)
 
-#define SLE_VEH_INCLUDE() {false, SL_VEH_INCLUDE, 0, 0, SL_MIN_VERSION, SL_MAX_VERSION, nullptr, 0, SlXvFeatureTest()}
-#define SLE_ST_INCLUDE() {false, SL_ST_INCLUDE, 0, 0, SL_MIN_VERSION, SL_MAX_VERSION, nullptr, 0, SlXvFeatureTest()}
+#define SLE_VEH_INCLUDE() {false, SL_VEH_INCLUDE, 0, 0, SL_MIN_VERSION, SL_MAX_VERSION, SLTAG_DEFAULT, nullptr, 0, SlXvFeatureTest()}
+#define SLE_ST_INCLUDE() {false, SL_ST_INCLUDE, 0, 0, SL_MIN_VERSION, SL_MAX_VERSION, SLTAG_DEFAULT, nullptr, 0, SlXvFeatureTest()}
 
 /**
  * Storage of global simple variables, references (pointers), and arrays.
@@ -732,7 +732,7 @@ inline constexpr void *SlVarWrapper(void* ptr)
  * @param extver   SlXvFeatureTest to test (along with from and to) which savegames have the field
  * @note In general, it is better to use one of the SLEG_* macros below.
  */
-#define SLEG_GENERAL_X(cmd, variable, type, length, from, to, extver) SaveLoad {true, cmd, type, length, from, to, SlVarWrapper<decltype(variable), cmd, type, length>((void*)&variable), sizeof(variable), extver}
+#define SLEG_GENERAL_X(cmd, variable, type, length, from, to, extver) SaveLoad {true, cmd, type, length, from, to, SLTAG_DEFAULT, SlVarWrapper<decltype(variable), cmd, type, length>((void*)&variable), sizeof(variable), extver}
 #define SLEG_GENERAL(cmd, variable, type, length, from, to) SLEG_GENERAL_X(cmd, variable, type, length, from, to, SlXvFeatureTest())
 
 /**
@@ -896,9 +896,8 @@ inline constexpr void *SlVarWrapper(void* ptr)
  * @param length Length of the empty space.
  * @param from   First savegame version that has the empty space.
  * @param to     Last savegame version that has the empty space.
- * @param extver SlXvFeatureTest to test (along with from and to) which savegames have empty space
  */
-#define SLEG_CONDNULL(length, from, to) {true, SL_ARR, SLE_FILE_U8 | SLE_VAR_NULL, length, from, to, (void*)nullptr, SlXvFeatureTest()}
+#define SLEG_CONDNULL(length, from, to) SaveLoad {true, SL_ARR, SLE_FILE_U8 | SLE_VAR_NULL, length, from, to, SLTAG_DEFAULT, nullptr, SlXvFeatureTest()}
 
 /**
  * Checks whether the savegame is below \a major.\a minor.
diff --git a/src/sl/saveload_types.h b/src/sl/saveload_types.h
index afeb1501f3..0928cfc781 100644
--- a/src/sl/saveload_types.h
+++ b/src/sl/saveload_types.h
@@ -131,6 +131,7 @@ struct SaveLoad {
 	uint16_t length;     ///< (conditional) length of the variable (eg. arrays) (max array size is 65536 elements)
 	SaveLoadVersion version_from; ///< save/load the variable starting from this savegame version
 	SaveLoadVersion version_to;   ///< save/load the variable until this savegame version
+	uint16_t label_tag;  ///< for labelling purposes
 	/* NOTE: This element either denotes the address of the variable for a global
 	 * variable, or the offset within a struct which is then bound to a variable
 	 * during runtime. Decision on which one to use is controlled by the function
@@ -140,6 +141,18 @@ struct SaveLoad {
 	SlXvFeatureTest ext_feature_test;  ///< extended feature test
 };
 
+inline constexpr SaveLoad SLTAG(uint16_t label_tag, SaveLoad save_load)
+{
+	save_load.label_tag = label_tag;
+	return save_load;
+}
+
+enum SaveLoadTags {
+	SLTAG_DEFAULT,
+	SLTAG_TABLE_UNKNOWN,
+	SLTAG_CUSTOM_START,
+};
+
 enum NamedSaveLoadFlags : uint8_t {
 	NSLF_NONE                     = 0,
 	NSLF_TABLE_ONLY               = 1 << 0,