diff --git a/docs/conf.py b/docs/conf.py
old mode 100644
new mode 100755
index 7373cb1..52c38ca
--- a/docs/conf.py
+++ b/docs/conf.py
@@ -1,6 +1,8 @@
 from crate.theme.rtd.conf.sql_99 import *
 
-html_baseurl = "https://sql-99.readthedocs.io/"
+# NOTE: `html_baseurl` used to be pinned to https://sql-99.readthedocs.io/ here.
+# It now comes from `crate.theme.rtd.conf.sql_99`, which derives it from the
+# Read the Docs environment for the docs.cratedb.com migration PoC.
 
 # Disable version chooser.
 html_context.update({
diff --git a/docs/requirements.txt b/docs/requirements.txt
index ced14fe..21c9592 100644
--- a/docs/requirements.txt
+++ b/docs/requirements.txt
@@ -1 +1,5 @@
-crate-docs-theme
+# TEMPORARY, for the docs.cratedb.com migration proof of concept.
+#
+# Restore the unpinned `crate-docs-theme` once the migration theme ships as a
+# final release.
+crate-docs-theme==0.51.0.dev0