--- a/cygwin.rst	Tue Dec 22 13:45:36 2020 +0200
+++ b/cygwin.rst	Wed Dec 30 23:13:21 2020 +0200
@@ -24,7 +24,7 @@
 native Windows Emacs can't determine file revision with my ``hg`` wrapper.
 
 https://cygwin.com/cygwin-ug-net/using-cygwinenv.html
-  The CYGWIN environment variable. Available options.
+  The ``CYGWIN`` environment variable. Available options.
 
 Set ``HOME`` env var::
 
@@ -282,13 +282,23 @@
 
   $ mkgroup -l > /etc/group
 
-Adding mount points.
-====================
+Adding mount points
+===================
+
+In Cygwin the 3rd parameter (FS type) has special meaning:
+
+* ``cygdrive`` defines prefix to Windows disk letters like ``c:``.
+* ``usertemp`` defines location of temp directory.
 
 ``/etc/fstab``::
 
-  C:/foo /bar/baz ntfs text,posix=0 0 0
-  /var /usr/var none bind
+  none /cygdrive    none binary,posix=0,user,noacl 0 0
+  c:/opt/   /opt    none binary,noacl,user,posix=0 0 0
+  d:/backup /backup none binary,noacl,user,posix=0 0 0
+  /var     /usr/var none bind
+
+https://cygwin.com/cygwin-ug-net/using.html#mount-table
+  The Cygwin Mount Table. Description of supported keys.
 
 Running X Window.
 =================