diff --git a/src/printer_lyb.c b/src/printer_lyb.c
index 14c4a0a..3b5b901 100644
--- a/src/printer_lyb.c
+++ b/src/printer_lyb.c
@@ -547,7 +547,11 @@
  *
  * @param[in] out Out structure.
  * @param[in] format Value prefix format.
- * @param[in] prefix_data Prefix data to print.
+ * @param[in] prefix_data Format-specific data to print:
+ *      LY_PREF_SCHEMA          - const struct lysp_module * (module used for resolving prefixes from imports)
+ *      LY_PREF_SCHEMA_RESOLVED - struct lyd_value_prefix * (sized array of pairs: prefix - module)
+ *      LY_PREF_XML             - const struct ly_set * (set with defined namespaces stored as ::lyxml_ns)
+ *      LY_PREF_JSON            - NULL
  * @param[in] lybctx LYB context.
  * @return LY_ERR value.
  */
diff --git a/src/printer_xml.c b/src/printer_xml.c
index 028456d..744f5be 100644
--- a/src/printer_xml.c
+++ b/src/printer_xml.c
@@ -127,6 +127,19 @@
     return NULL;
 }
 
+/**
+ * @brief Print prefix data.
+ *
+ * @param[in] ctx XML printer context.
+ * @param[in] format Value prefix format.
+ * @param[in] prefix_data Format-specific data to print:
+ *      LY_PREF_SCHEMA          - const struct lysp_module * (module used for resolving prefixes from imports)
+ *      LY_PREF_SCHEMA_RESOLVED - struct lyd_value_prefix * (sized array of pairs: prefix - module)
+ *      LY_PREF_XML             - const struct ly_set * (set with defined namespaces stored as ::lyxml_ns)
+ *      LY_PREF_JSON            - NULL
+ * @param[in] prefix_opts Prefix options changing the meaning of parameters.
+ * @return LY_ERR value.
+ */
 static void
 xml_print_ns_prefix_data(struct xmlpr_ctx *ctx, LY_PREFIX_FORMAT format, void *prefix_data, uint32_t prefix_opts)
 {
diff --git a/src/tree_data.h b/src/tree_data.h
index 74180bc..92b449d 100644
--- a/src/tree_data.h
+++ b/src/tree_data.h
@@ -495,7 +495,7 @@
     struct ly_opaq_name name;       /**< attribute name with module information */
     const char *value;              /**< attribute value */
     LY_PREFIX_FORMAT format;        /**< format of the attribute and any prefixes, ::LY_PREF_XML or ::LY_PREF_JSON */
-    void *val_prefix_data;          /**< format-specific prefix data (see ::ly_resolve_prefix()) */
+    void *val_prefix_data;          /**< format-specific prefix data */
     uint32_t hints;                 /**< additional information about from the data source, see the [hints list](@ref lydhints) */
 
 };
@@ -704,7 +704,7 @@
     struct ly_opaq_name name;       /**< node name with module information */
     const char *value;              /**< original value */
     LY_PREFIX_FORMAT format;        /**< format of the node and any prefixes, ::LY_PREF_XML or ::LY_PREF_JSON */
-    void *val_prefix_data;          /**< format-specific prefix data (see ::ly_resolve_prefix()) */
+    void *val_prefix_data;          /**< format-specific prefix data */
     uint32_t hints;                 /**< additional information about from the data source, see the [hints list](@ref lydhints) */
 
     const struct ly_ctx *ctx;       /**< libyang context */
diff --git a/src/tree_data_internal.h b/src/tree_data_internal.h
index 35a3839..5427621 100644
--- a/src/tree_data_internal.h
+++ b/src/tree_data_internal.h
@@ -186,7 +186,11 @@
  * @param[in] value_len Length of @p value, must be set correctly.
  * @param[in,out] dynamic Flag if @p value is dynamically allocated, is adjusted when @p value is consumed.
  * @param[in] format Input format of @p value and @p ns.
- * @param[in] val_prefix_data Format-specific prefix data, param is spent (even in case the function fails).
+ * @param[in] val_prefix_data Format-specific prefix data, param is spent (even in case the function fails):
+ *      LY_PREF_SCHEMA          - const struct lysp_module * (module used for resolving prefixes from imports)
+ *      LY_PREF_SCHEMA_RESOLVED - struct lyd_value_prefix * (sized array of pairs: prefix - module)
+ *      LY_PREF_XML             - const struct ly_set * (set with defined namespaces stored as ::lyxml_ns)
+ *      LY_PREF_JSON            - NULL
  * @param[in] hints [Hints](@ref lydhints) from the parser regarding the node/value type.
  * @param[out] node Created node.
  * @return LY_SUCCESS on success.
@@ -432,7 +436,11 @@
  * @brief Free stored prefix data.
  *
  * @param[in] format Format of the prefixes.
- * @param[in] prefix_data Prefix data to free.
+ * @param[in] prefix_data Format-specific data to free:
+ *      LY_PREF_SCHEMA          - const struct lysp_module * (module used for resolving prefixes from imports)
+ *      LY_PREF_SCHEMA_RESOLVED - struct lyd_value_prefix * (sized array of pairs: prefix - module)
+ *      LY_PREF_XML             - const struct ly_set * (set with defined namespaces stored as ::lyxml_ns)
+ *      LY_PREF_JSON            - NULL
  */
 void ly_free_prefix_data(LY_PREFIX_FORMAT format, void *prefix_data);