diff --git a/book.toml b/book.toml
index 16a9d6f80b..65d8616b18 100644
--- a/book.toml
+++ b/book.toml
@@ -5,7 +5,6 @@ authors = ["The Rust Community"]
 
 [output.html.playpen]
 editable = true
-editor = "ace"
 line-numbers = true
 
 [output.html.fold]
@@ -27,4 +26,5 @@ edition = "2021"
 extra-watch-dirs = ["po"]
 
 [preprocessor.gettext]
+optional = true
 after = ["links"]