--- a/README	Thu May 14 23:27:43 2020 -0400
+++ b/README	Tue Jun 02 21:25:59 2020 +0000
@@ -71,8 +71,10 @@
 Bugs and Patches
 ----------------
 
-The file `BUGS` explains the recommended procedure for reporting bugs
-on the [bug tracker](https://bugs.octave.org) or contributing patches.
+The file `BUGS` (or `doc/interpreter/bugs.txi`) explains the recommended
+procedure for reporting bugs on the [bug tracker](https://bugs.octave.org)
+or contributing patches; online documentation is also available
+[here](https://www.gnu.org/software/octave/bugs.html).
 
 Documentation
 -------------

--- a/doc/interpreter/install.txi	Thu May 14 23:27:43 2020 -0400
+++ b/doc/interpreter/install.txi	Tue Jun 02 21:25:59 2020 +0000
@@ -233,7 +233,7 @@
 (@code{fft}, @code{ifft}, @code{fft2}, etc.)
 
 @item FLTK
-Portable GUI toolkit (@url{http://www.fltk.org}).  FLTK is currently
+Portable GUI toolkit (@url{http://www.fltk.org}).  FLTK can be
 used to provide windows for Octave's OpenGL-based graphics functions.
 
 @item fontconfig
@@ -256,7 +256,8 @@
 
 @item gnuplot
 Interactive graphics program (@url{http://www.gnuplot.info}).  gnuplot
-is currently the default graphics renderer for Octave.
+can be used as a graphics renderer for Octave; prior to Octave 4.0,
+gnuplot was the default graphics renderer.
 
 @item GraphicsMagick++
 Image processing library (@url{http://www.graphicsmagick.org}).
@@ -281,11 +282,12 @@
 
 @item OpenGL
 API for portable 2-D and 3-D graphics (@url{https://www.opengl.org}).  An
-OpenGL implementation is required to provide Octave's OpenGL-based
+OpenGL implementation can be used to provide a renderer for Octave's
 graphics functions.  Octave's OpenGL-based graphics functions usually
 outperform the gnuplot-based graphics functions because plot data can be
 rendered directly instead of sending data and commands to gnuplot for
-interpretation and rendering.
+interpretation and rendering.  Since Octave 4.0, the default graphics
+renderer (@qcode{"qt"}) has been OpenGL-based.
 
 @item PortAudio
 PortAudio (@url{http://www.portaudio.com/}) provides a very simple API
@@ -314,7 +316,9 @@
 @item Qt
 GUI and utility libraries (@url{https://www.qt.io}).  Qt is required for
 building the GUI@.  It is a large framework, but the only components
-required are the GUI, core, and network modules.
+required are the GUI, core, and network modules.  Since Octave 4.0, the
+default graphics renderer (@qcode{"qt"}) has been Qt-based, which has
+been OpenGL-based.
 
 @item SuiteSparse
 Sparse matrix factorization library