diff --git a/src/js/dialogs/sandbox.js b/src/js/dialogs/sandbox.js
index 8e13b565..6f5ed23f 100644
--- a/src/js/dialogs/sandbox.js
+++ b/src/js/dialogs/sandbox.js
@@ -18,7 +18,14 @@ exports.dialog = {
         '',
         'PS: Want to go straight to a sandbox next time?',
         'Try out ',
-        '[this special link](https://pcottle.github.io/learnGitBranching/?NODEMO)'
+        '[this special link](https://pcottle.github.io/learnGitBranching/?NODEMO)',
+        '',
+        'PPS: GitHub (and the industry at large) is moving to naming the default branch as `main` instead of `master` ',
+        'with [more details available here](https://github.com/github/renaming). In order to accommodate this change in ',
+        'a backwards-compatible way, these two names will be considered aliases of each other, with `main` being ',
+        'the preferred one to display. We\'ve made a best-effort attempt to update all of the level content, but ',
+        'there will be a long-tail of areas we have missed. Please submit a PR (or open an issue) if you spot any ',
+        'egregious ones, and thanks for helping move away from biased terminology.'
       ]
     }
   }],