diff --git a/src/console_cmds.cpp b/src/console_cmds.cpp
--- a/src/console_cmds.cpp
+++ b/src/console_cmds.cpp
@@ -385,7 +385,8 @@ DEF_CONSOLE_CMD(ConSave)
 	}
 
 	if (argc == 2) {
-		char *filename = str_fmt("%s.sav", argv[1]);
+		std::string filename = argv[1];
+		filename += ".sav";
 		IConsolePrint(CC_DEFAULT, "Saving map...");
 
 		if (SaveOrLoad(filename, SLO_SAVE, DFT_GAME_FILE, SAVE_DIR) != SL_OK) {
@@ -393,7 +394,6 @@ DEF_CONSOLE_CMD(ConSave)
 		} else {
 			IConsolePrint(CC_INFO, "Map successfully saved to '{}'.", filename);
 		}
-		free(filename);
 		return true;
 	}
 
diff --git a/src/string.cpp b/src/string.cpp
--- a/src/string.cpp
+++ b/src/string.cpp
@@ -145,24 +145,6 @@ char *stredup(const char *s, const char 
 }
 
 /**
- * Format, "printf", into a newly allocated string.
- * @param str The formatting string.
- * @return The formatted string. You must free this!
- */
-char *CDECL str_fmt(const char *str, ...)
-{
-	char buf[4096];
-	va_list va;
-
-	va_start(va, str);
-	int len = vseprintf(buf, lastof(buf), str, va);
-	va_end(va);
-	char *p = MallocT<char>(len + 1);
-	memcpy(p, buf, len + 1);
-	return p;
-}
-
-/**
  * Format a byte array into a continuous hex string.
  * @param data Array to format
  * @return Converted string.
diff --git a/src/string_func.h b/src/string_func.h
--- a/src/string_func.h
+++ b/src/string_func.h
@@ -38,8 +38,6 @@ char *stredup(const char *src, const cha
 int CDECL seprintf(char *str, const char *last, const char *format, ...) WARN_FORMAT(3, 4) NOACCESS(2);
 int CDECL vseprintf(char *str, const char *last, const char *format, va_list ap) WARN_FORMAT(3, 0) NOACCESS(2);
 
-char *CDECL str_fmt(const char *str, ...) WARN_FORMAT(1, 2);
-
 std::string FormatArrayAsHex(span<const byte> data);
 
 void StrMakeValidInPlace(char *str, const char *last, StringValidationSettings settings = SVS_REPLACE_WITH_QUESTION_MARK) NOACCESS(2);