Minor documentation updates.

include/freetype/freetype.h

@@ -1233,8 +1233,8 @@ FT_BEGIN_HEADER
    *   FT_FACE_FLAG_VARIATION ::
    *     [Since 2.9] Set if the current face (or named instance) has been
    *     altered with @FT_Set_MM_Design_Coordinates,
-   *     @FT_Set_Var_Design_Coordinates, or @FT_Set_Var_Blend_Coordinates.
-   *     This flag is unset by a call to @FT_Set_Named_Instance.
+   *     @FT_Set_Var_Design_Coordinates, @FT_Set_Var_Blend_Coordinates, or
+   *     @FT_Set_MM_WeightVector to select a non-default instance.
    *
    *   FT_FACE_FLAG_SVG ::
    *     [Since 2.12] The face has an 'SVG~' OpenType table.
@@ -1449,8 +1449,8 @@ FT_BEGIN_HEADER
    *
    * @description:
    *   A macro that returns true whenever a face object has been altered by
-   *   @FT_Set_MM_Design_Coordinates, @FT_Set_Var_Design_Coordinates, or
-   *   @FT_Set_Var_Blend_Coordinates.
+   *   @FT_Set_MM_Design_Coordinates, @FT_Set_Var_Design_Coordinates,
+   *   @FT_Set_Var_Blend_Coordinates, or @FT_Set_MM_WeightVector.
    *
    * @since:
    *   2.9
@@ -4264,9 +4264,10 @@ FT_BEGIN_HEADER
    *
    *   [Since 2.9] Special PostScript names for named instances are only
    *   returned if the named instance is set with @FT_Set_Named_Instance (and
-   *   the font has corresponding entries in its 'fvar' table).  If
-   *   @FT_IS_VARIATION returns true, the algorithmically derived PostScript
-   *   name is provided, not looking up special entries for named instances.
+   *   the font has corresponding entries in its 'fvar' table or is the
+   *   default named instance).  If @FT_IS_VARIATION returns true, the
+   *   algorithmically derived PostScript name is provided, not looking up
+   *   special entries for named instances.
    */
   FT_EXPORT( const char* )
   FT_Get_Postscript_Name( FT_Face  face );

include/freetype/internal/tttypes.h

@@ -1200,12 +1200,16 @@ FT_BEGIN_HEADER
    *   mm ::
    *     A pointer to the Multiple Masters service.
    *
-   *   var ::
-   *     A pointer to the Metrics Variations service.
+   *   tt_var ::
+   *     A pointer to the Metrics Variations service for the "truetype"
+   *     driver.
    *
-   *   hdmx ::
-   *     The face's horizontal device metrics ('hdmx' table).  This table is
-   *     optional in TrueType/OpenType fonts.
+   *   face_var ::
+   *     A pointer to the Metrics Variations service for this `TT_Face`'s
+   *     driver.
+   *
+   *   psaux ::
+   *     A pointer to the PostScript Auxiliary service.
    *
    *   gasp ::
    *     The grid-fitting and scaling properties table ('gasp').  This table
@@ -1357,14 +1361,6 @@ FT_BEGIN_HEADER
    *     A mapping between the strike indices exposed by the API and the
    *     indices used in the font's sbit table.
    *
-   *   cpal ::
-   *     A pointer to data related to the 'CPAL' table.  `NULL` if the table
-   *     is not available.
-   *
-   *   colr ::
-   *     A pointer to data related to the 'COLR' table.  `NULL` if the table
-   *     is not available.
-   *
    *   kern_table ::
    *     A pointer to the 'kern' table.
    *
@@ -1405,6 +1401,18 @@ FT_BEGIN_HEADER
    *
    *   ebdt_size ::
    *     The size of the sbit data table.
+   *
+   *   cpal ::
+   *     A pointer to data related to the 'CPAL' table.  `NULL` if the table
+   *     is not available.
+   *
+   *   colr ::
+   *     A pointer to data related to the 'COLR' table.  `NULL` if the table
+   *     is not available.
+   *
+   *   svg ::
+   *     A pointer to data related to the 'SVG' table.  `NULL` if the table
+   *     is not available.
    */
   typedef struct  TT_FaceRec_
   {
@@ -1462,7 +1470,7 @@ FT_BEGIN_HEADER
     /* a typeless pointer to the FT_Service_MetricsVariationsRec table */
     /* used to handle the HVAR, VVAR, and MVAR OpenType tables by this */
     /* TT_Face's driver                                                */
-    void*                 face_var;
+    void*                 face_var;             /* since 2.13.1 */
 #endif
 
     /* a typeless pointer to the PostScript Aux service */

src/truetype/ttgxvar.c

@@ -2965,7 +2965,8 @@
    *     An array of `num_coords', each between [-1,1].
    *
    * @Return:
-   *   FreeType error code.  0 means success.
+   *   FreeType error code.  0 means success, -1 means success and unchanged
+   *   axis values.
    */
   FT_LOCAL_DEF( FT_Error )
   TT_Set_MM_Blend( TT_Face    face,
@@ -3012,7 +3013,8 @@
    *     An array of `num_coords', each between [-1,1].
    *
    * @Return:
-   *   FreeType error code.  0 means success.
+   *   FreeType error code.  0 means success, -1 means success and unchanged
+   *   axis values.
    */
   FT_LOCAL_DEF( FT_Error )
   TT_Get_MM_Blend( TT_Face    face,