diff --git a/CHANGES b/CHANGES
index 6299bf6..305520d 100644
--- a/CHANGES
+++ b/CHANGES
@@ -20,6 +20,14 @@ The following are the changes from calc version 2.12.6.0 to date:
 
 	https://github.com/lcn2/calc
 
+    NOTE: The calc GitHub repository represents the an active
+	  development stream.  While an effort will be made to keep
+	  the master branch of the calc GitHub repository in working
+	  order, that tree may be unstable.  Those wishing for more
+	  reliable releases use releases found at calc mirror sites:
+
+	    http://www.isthe.com/chongo/tech/comp/calc/calc-mirror.html
+
     Renamed README to README.FIRST.  Added README.md for the
     GitHub repository.
 
@@ -34,6 +42,13 @@ The following are the changes from calc version 2.12.6.0 to date:
     Updated the calc(1) man page and 'help file' to explain about
     reading from standard input (stdin).
 
+    Added some clarifying remarks for 'help ptest' explaining that
+    the ptest builtin can return 1 is some cases where the test
+    value is a psuedoprime.
+
+    Removed duplicate copyright comments from the help/builtin that
+    is built.
+
 
 The following are the changes from calc version 2.12.5.4 to 2.12.5.6:
 
diff --git a/Makefile.ship b/Makefile.ship
index d7a7142..8b68804 100644
--- a/Makefile.ship
+++ b/Makefile.ship
@@ -1923,6 +1923,7 @@ HELP_PASSDOWN= \
     CP=${CP} \
     EXT=${EXT} \
     FMT=${FMT} \
+    GREP=${GREP} \
     HELPDIR="${HELPDIR}" \
     ICFLAGS="${ICFLAGS}" \
     ILDFLAGS="${ILDFLAGS}" \
diff --git a/help/Makefile b/help/Makefile
index de13418..a59eff5 100644
--- a/help/Makefile
+++ b/help/Makefile
@@ -168,6 +168,7 @@ Q=@
 LCC= cc
 ICFLAGS=
 ILDFLAGS=
+GREP= egrep
 CHMOD= chmod
 SED= sed
 SORT= sort
@@ -596,7 +597,7 @@ builtin: builtin.top builtin.end ../func.c funclist.sed
 	    -I.. funclist.c -c 2>/dev/null
 	${Q} ${LCC} ${ILDFLAGS} funclist.o -o funclist${EXT}
 	${Q} ${RM} -f builtin
-	${Q} ${CAT} builtin.top > builtin
+	${Q} ${GREP} -v '^#'  builtin.top > builtin
 	${Q} ./funclist${EXT} | \
 	    ${SED} -e 's/^/	/' -e 's/[	 ][	 ]*$$//' >> builtin
 	${Q} ${CAT} builtin.end >> builtin
diff --git a/help/builtin.end b/help/builtin.end
index 87b8bb8..0467845 100644
--- a/help/builtin.end
+++ b/help/builtin.end
@@ -199,7 +199,7 @@
 	For convenience, any non-integer value is assumed to mean "frac",
 	and any integer >= 2^64 is assumed to mean "exp".
 
-## Copyright (C) 1999-2007  Landon Curt Noll
+## Copyright (C) 1999-2017  Landon Curt Noll
 ##
 ## Calc is open software; you can redistribute it and/or modify it under
 ## the terms of the version 2.1 of the GNU Lesser General Public License
diff --git a/help/ptest b/help/ptest
index 7e5631d..e2e3e67 100644
--- a/help/ptest
+++ b/help/ptest
@@ -39,6 +39,14 @@ DESCRIPTION
     trivial (n is always a strong probable prime for these bases), it
     is sufficient to consider 1 < b < n - 1.
 
+    Note that if ptest returns 1, this does not mean that n is
+    prime!  If n is composit (not prime) and a pseudoprime then
+    ptest may return 1.  For this reason, if ptest returns 1, this
+    is not proof that n is prime.
+
+    If ptest returns 0, then this is proof that n is not prime
+    (composit).
+
     The bases for ptest(n, count, skip) are selected as follows:
 
 	skip = 0:	random in [2, n-2]
@@ -56,14 +64,14 @@ DESCRIPTION
     with random base b will return 1 if n is composite is always
     less than 1/4, so with count = k, the probability is less
     than 1/4^k.	 For most values of n the probability is much
-    smaller, possible zero.
+    smaller (possibly zero).
 
 RUNTIME
-    If n is composite, ptest(n, 1, skip) is usually faster than
-    ptest(n, -1, skip), much faster if n is divisible by a small
-    prime.  If n is prime, ptest(n, -1, skip) is usually faster than
-    ptest(n, 1, skip), possibly much faster if n < 2^32, only slightly
-    faster if n > 2^32.
+    If n is composite, ptest(n, 1, skip) (where skip > 0) is usually
+    faster than ptest(n, -1, skip), and much faster if n is divisible
+    by a small prime.  If n is prime, ptest(n, -1, skip) is usually
+    faster than ptest(n, 1, skip), possibly much faster if n < 2^32,
+    only slightly faster if n > 2^32.
 
     If n is a large prime (say 50 or more decimal digits), the runtime
     for ptest(n, count, skip) will usually be roughly K * abs(count) *
@@ -129,7 +137,7 @@ SEE ALSO
     factor, isprime, lfactor, nextcand, nextprime, prevcand, prevprime,
     pfact, pix
 
-## Copyright (C) 1999-2006  Landon Curt Noll
+## Copyright (C) 1999-2006,2017  Landon Curt Noll
 ##
 ## Calc is open software; you can redistribute it and/or modify it under
 ## the terms of the version 2.1 of the GNU Lesser General Public License