diff --git a/README.rst b/README.rst
index aeab5b5..a5bfcbb 100644
--- a/README.rst
+++ b/README.rst
@@ -4,6 +4,17 @@ atsphinx-linebreak
 
 Enable line-break for everywhere.
 
+Overview
+========
+
+This is Sphinx-extension to inject extra node into line-break of source (LF) when it build.
+You can write source likely GitHub Flavored Markdown ("Newline" code means as "line-feed of content") by using it.
+
+.. note::
+
+   This affects to any sources including reStructuredText.
+   If you want to change behavior, post PR or issue into GitHub.
+
 Getting started
 ===============
 
diff --git a/src/atsphinx/linebreak/__init__.py b/src/atsphinx/linebreak/__init__.py
index f0113c1..be91f1e 100644
--- a/src/atsphinx/linebreak/__init__.py
+++ b/src/atsphinx/linebreak/__init__.py
@@ -12,6 +12,7 @@ class line_break(nodes.Element, nodes.General):  # noqa: D101
 
 def visit_line_break(self, node: line_break):
     """Inject br tag (html only)."""
+    # NOTE: It can change inserting token by configuration.
     self.body.append("<br>")
 
 
@@ -22,7 +23,10 @@ def depart_line_break(self, node: line_break):
 
 def inject_line_break(app: Sphinx, doctree: nodes.document):
     """Split text by line-break and inject marker node."""
+    # NOTE: doctree["source"] has file path of source.
+    # If it want to change proc by file type, see this.
     for text in doctree.findall(nodes.Text):
+        # NOTE: This may not catch CR+LF (windows) pattern.
         if "\n" not in text:
             continue
         splitted = [(nodes.Text(t), line_break()) for t in text.split("\n")]