diff --git a/Makefile b/Makefile
index da637f6a..a31783c9 100644
--- a/Makefile
+++ b/Makefile
@@ -58,6 +58,9 @@ post-build-tests: post-build-tests-fast
 ## overwritten content is under version control
 manual-updates: manual-update-summaries-file
 
+## All manual checks that can be run by a human
+manual-checks: manual-check-diff-sha256sums
+
 
 
 
@@ -71,7 +74,9 @@ ERROR_ON_OUTPUT="sed '1s/^/ERROR:\n/' | if grep . ; then sed 1iERROR ; false ; e
 ## This should not affect webpage output.
 build:
 	$S export LANG=C.UTF-8 ; eval $(JEKYLL_COMMAND) 2>&1 | tee $(JEKYLL_LOG)
-
+	$S grep -r -L 'Note: this file is built non-deterministically' _site/ \
+	  | egrep -v 'sha256sums.txt' \
+	  | xargs sha256sum > _site/sha256sums.txt
 
 ## Jekyll annoyingly returns success even when it emits errors and
 ## exceptions, so we'll grep its output for error strings
@@ -181,3 +186,14 @@ manual-update-summaries-file:
 	$S echo "{%comment%}AUTOMATICALLY-GENERATED FILE: DO NOT EDIT THIS FILE" > _includes/helpers/summaries.md
 	$S echo "This file is licensed under the terms of its source texts{%endcomment%}" >> _includes/helpers/summaries.md
 	$S grep -rh --exclude='*summaries.md' 'assign summary_' _includes/ | sort >> _includes/helpers/summaries.md
+
+manual-check-diff-sha256sums:
+## A manually-run command to check the locally-built
+## _site/sha256sums.txt file against the same file on the webserver to
+## see if any files were built differently upstream from what we have
+## locally
+	$S echo "Files listed below (if any) have different hashes"
+	$S curl -s -o- https://bitcoin.org/sha256sums.txt \
+	  | sort - _site/sha256sums.txt \
+	  | uniq -u \
+	  | sort -k2
diff --git a/_templates/about-us.html b/_templates/about-us.html
index 1594c2cf..39ef1659 100644
--- a/_templates/about-us.html
+++ b/_templates/about-us.html
@@ -5,6 +5,7 @@
 layout: base
 id: about-us
 ---
+<!-- Note: this file is built non-deterministically -->
 <h1>{% translate pagetitle %}</h1>
 <p class="summary">{% translate pagedesc %}</p>
 
diff --git a/_templates/development.html b/_templates/development.html
index c53b8fed..83282a33 100755
--- a/_templates/development.html
+++ b/_templates/development.html
@@ -5,6 +5,7 @@
 layout: base
 id: development
 ---
+<!-- Note: this file is built non-deterministically -->
 <h1>{% translate pagetitle %}</h1>
 <p class="summary">{% translate summary %}</p>
 
diff --git a/_templates/events.html b/_templates/events.html
index d1f8f764..d18c1c14 100644
--- a/_templates/events.html
+++ b/_templates/events.html
@@ -5,6 +5,7 @@
 layout: base
 id: events
 ---
+<!-- Note: this file is built non-deterministically -->
 <link rel="alternate" type="application/rss+xml" href="/en/rss/events.rss" title="Bitcoin conferences and events">
 <h1>{% translate pagetitle %}<a type="application/rss+xml" href="/en/rss/events.rss"><img src="/img/icons/icon_rss.svg" alt="rss" class="rssicon"></a></h1>
 <p class="summary">{% translate pagedesc %}</p>
diff --git a/en/rss/events.rss b/en/rss/events.rss
index 05ce6e8e..b758cbeb 100644
--- a/en/rss/events.rss
+++ b/en/rss/events.rss
@@ -4,6 +4,7 @@
 ---
 <?xml version="1.0" encoding="UTF-8"?>
 <rss version="2.0">
+<!-- Note: this file is built non-deterministically -->
 <channel>
 	<title>Bitcoin conferences and events</title>
 	<link>https://bitcoin.org/en/events</link>