data tree DOC clarify date-and-time timezone
diff --git a/src/tree_data.h b/src/tree_data.h
index 89aad8a..e50b180 100644
--- a/src/tree_data.h
+++ b/src/tree_data.h
@@ -2318,7 +2318,7 @@
*
* @param[in] time UNIX timestamp.
* @param[in] fractions_s Fractions of a second, if any.
- * @param[out] str String date-and-time value.
+ * @param[out] str String date-and-time value in the local timezone.
* @return LY_ERR value.
*/
LY_ERR ly_time_time2str(time_t time, const char *fractions_s, char **str);
@@ -2336,7 +2336,7 @@
* @brief Convert timespec into date-and-time string value.
*
* @param[in] ts Timespec.
- * @param[out] str String date-and-time value.
+ * @param[out] str String date-and-time value in the local timezone.
* @return LY_ERR value.
*/
LY_ERR ly_time_ts2str(const struct timespec *ts, char **str);