diff --git a/constraints-juju29.txt b/constraints-juju29.txt
index a8c2cc50..ba318b49 100644
--- a/constraints-juju29.txt
+++ b/constraints-juju29.txt
@@ -1,3 +1,11 @@
-# 2.9.45.0 - https://github.com/juju/python-libjuju/pull/975
-# 2.9.46.0
+# NOTE: this constraints file can be (and will be) consumed by downstream users.
+#
+# Known consumers:
+# * zosci-config: job definitions that declare what juju version (snap channel)
+#   is used in tandem with this constraints file to lockdown python-libjuju
+#   version.
+# * zaza-openstack-tests
+#
+# Reasons to block the use of a release:
+# * 2.9.45, 2.9.46 - https://github.com/juju/python-libjuju/pull/975
 juju>=2.9.0,<3.0.0,!=2.9.45,!=2.9.46
diff --git a/constraints-juju31.txt b/constraints-juju31.txt
index f54dea1e..f85e9e1b 100644
--- a/constraints-juju31.txt
+++ b/constraints-juju31.txt
@@ -1 +1,9 @@
+# NOTE: this constraints file can be (and will be) consumed by downstream users.
+#
+# Known consumers:
+# * zosci-config: job definitions that declare what juju version (snap channel)
+#   is used in tandem with this constraints file to lockdown python-libjuju
+#   version.
+# * zaza-openstack-tests
+#
 juju>=3.1.0,<3.2.0
diff --git a/constraints-juju32.txt b/constraints-juju32.txt
index 7c6a709f..76eaa903 100644
--- a/constraints-juju32.txt
+++ b/constraints-juju32.txt
@@ -1 +1,9 @@
+# NOTE: this constraints file can be (and will be) consumed by downstream users.
+#
+# Known consumers:
+# * zosci-config: job definitions that declare what juju version (snap channel)
+#   is used in tandem with this constraints file to lockdown python-libjuju
+#   version.
+# * zaza-openstack-tests
+#
 juju>=3.2.0,<3.3.0
diff --git a/constraints-juju33.txt b/constraints-juju33.txt
index 67d9ebfd..f5263fa0 100644
--- a/constraints-juju33.txt
+++ b/constraints-juju33.txt
@@ -1 +1,9 @@
+# NOTE: this constraints file can be (and will be) consumed by downstream users.
+#
+# Known consumers:
+# * zosci-config: job definitions that declare what juju version (snap channel)
+#   is used in tandem with this constraints file to lockdown python-libjuju
+#   version.
+# * zaza-openstack-tests
+#
 juju>=3.3.0,<3.4.0