Improve the API docs

python/core/auto_generated/qgsmapsettings.sip.in

@@ -74,6 +74,23 @@ Set coordinates of the rectangle which should be rendered.
 The actual visible extent used for rendering could be slightly different
 since the given extent may be expanded in order to fit the aspect ratio
 of output size. Use visibleExtent() to get the resulting extent.
+%End
+
+    double extentBuffer() const;
+%Docstring
+Returns the buffer to use around the visible extent for rendering symbols whose
+corresponding geometries are outside the visible extent.
+
+.. versionadded:: 3.10
+%End
+
+    void setExtentBuffer( double buffer );
+%Docstring
+Sets the buffer to use around the visible extent for rendering symbols whose
+corresponding geometries are outside the visible extent. This is useful when
+using tiles to avoid cut symbols at tile boundaries.
+
+.. versionadded:: 3.10
 %End
 
     QSize outputSize() const;

python/server/auto_generated/qgsserverprojectutils.sip.in

@@ -156,7 +156,7 @@ Returns the quality for WMS images defined in a QGIS project.
 
   int wmsTileBuffer( const QgsProject &project );
 %Docstring
-Returns the tile buffer for WMS images defined in a QGIS project.
+Returns the tile buffer in pixels for WMS images defined in a QGIS project.
 
 :param project: the QGIS project
 

src/core/qgsmapsettings.h

@@ -103,11 +103,16 @@ class CORE_EXPORT QgsMapSettings
     void setExtent( const QgsRectangle &rect, bool magnified = true );
 
     /**
+     * Returns the buffer to use around the visible extent for rendering symbols whose
+     * corresponding geometries are outside the visible extent.
      * \since QGIS 3.10
      */
     double extentBuffer() const;
 
     /**
+     * Sets the buffer to use around the visible extent for rendering symbols whose
+     * corresponding geometries are outside the visible extent. This is useful when
+     * using tiles to avoid cut symbols at tile boundaries.
      * \since QGIS 3.10
      */
     void setExtentBuffer( double buffer );