put message in log instead of message box

python/core/auto_generated/qgsbrowsermodel.sip.in

@@ -125,7 +125,9 @@ items, i.e. it does not fetch children.
 :param uri: item uri
 :param index: the current index of the parent (to search for children)
 
-:return: model index, invalid if item not found *
+:return: model index, invalid if item not found
+
+.. versionadded:: 3.6
 %End
 
  void connectItem( QgsDataItem *item ) /Deprecated/;

src/app/browser/qgsinbuiltdataitemproviders.cpp

@@ -23,6 +23,7 @@
 #include "qgsnative.h"
 #include "qgisapp.h"
 #include "qgsmessagebar.h"
+#include "qgsmessagelog.h"
 #include "qgsnewnamedialog.h"
 #include "qgsbrowsermodel.h"
 #include "qgsbrowserdockwidget_p.h"
@@ -484,7 +485,7 @@ void QgsLayerItemGuiProvider::deleteLayers( const QStringList &itemPaths )
     QgsLayerItem *item = qobject_cast<QgsLayerItem *>( QgisApp::instance()->browserModel()->dataItem( QgisApp::instance()->browserModel()->findUri( itemPath ) ) );
     if ( !item )
     {
-      QMessageBox::information( QgisApp::instance(), tr( "Delete Layer" ), tr( "Item with path %1 not found anymore." ).arg( itemPath ) );
+      QgsMessageLog::logMessage( tr( "Item with path %1 no longer exists." ).arg( itemPath ) );
       return;
     }
     if ( !item->deleteLayer() )

src/core/qgsbrowsermodel.h

@@ -141,7 +141,10 @@ class CORE_EXPORT QgsBrowserModel : public QAbstractItemModel
      * items, i.e. it does not fetch children.
      * \param uri item uri
      * \param index the current index of the parent (to search for children)
-     * \returns model index, invalid if item not found */
+     * \returns model index, invalid if item not found
+     *
+     * \since QGIS 3.6
+     */
     QModelIndex findUri( const QString &uri, QModelIndex index = QModelIndex() );
 
     /**