diff --git a/doc/bashref.texi b/doc/bashref.texi
index c0f4a2f..8bf0ff9 100644
--- a/doc/bashref.texi
+++ b/doc/bashref.texi
@@ -1197,7 +1197,14 @@ This pipe is established before any redirections specified by the
 command (@pxref{Redirections}).
 The file descriptors can be utilized as arguments to shell commands
 and redirections using standard word expansions.
-The file descriptors are not available in subshells.
+The file descriptors are not available in subshells other than those
+created by command and process substitutions (see the descriptions
+the substitutions in @ref{Command Substitution} and
+@ref{Process Substitution}, respectively).  While it is not an error
+to create more than one coprocess, the shell only remembers the last
+one created.  The forgotten coprocess(es) will have their file
+descriptors available in a subshell because the subshell only closes
+the file descriptors of the remembered coprocess.
 
 The process ID of the shell spawned to execute the coprocess is
 available as the value of the variable @env{NAME}_PID.
@@ -3025,6 +3032,12 @@ shell's parent, and traps ignored by the shell are ignored
 A command invoked in this separate environment cannot affect the
 shell's execution environment.
 
+Command substitution and process substitution are invoked in a
+separate execution environment that starts as an exact duplicate of
+the execution environment of the shell.  As before, any command within
+the separate execution environment cannot affect the shell's execution
+environment.
+
 Command substitution, commands grouped with parentheses,
 and asynchronous commands are invoked in a
 subshell environment that is a duplicate of the shell environment,