diff --git a/.gitignore b/.gitignore
index 28b4c4d..2b7e68c 100644
--- a/.gitignore
+++ b/.gitignore
@@ -30,4 +30,10 @@ vendor/
 .vagrant
 
 ## Ignore lock file during development / not used on platform anyway
-composer.lock
+## Temporarily allow deployment of select contrib modules (by permitting the lock file).
+## So far we are using select contrib modules for migration only, which wouldn't
+## technically ever be required on the platform... but they'd have to be uninstalled
+## before the configuration were deployed.  We need to at least report to sites "your
+## composer.json/composer.lock file called for modules X and Y, which were not deployed"
+## to make it easier to understand the resulting config import error  :-/
+# composer.lock