diff --git a/bootstrap.example.toml b/bootstrap.example.toml
index b59f112bdfb8..73e93ccbe420 100644
--- a/bootstrap.example.toml
+++ b/bootstrap.example.toml
@@ -392,7 +392,8 @@
 # For example, to build Miri with tracing support, use `tool.miri.features = ["tracing"]`
 #
 # The default value for the `features` array is `[]`. However, please note that other flags in
-# `bootstrap.toml` might influence the features enabled for some tools.
+# `bootstrap.toml` might influence the features enabled for some tools. Also, enabling features
+# in tools which are not part of the internal "extra-features" preset might not always work.
 #build.tool.TOOL_NAME.features = [FEATURE1, FEATURE2]
 
 # Verbosity level: 0 == not verbose, 1 == verbose, 2 == very verbose, 3 == print environment variables on each rustc invocation