diff --git a/Render-a-File.md b/Render-a-File.md
index bd044e8..1a59229 100644
--- a/Render-a-File.md
+++ b/Render-a-File.md
@@ -42,10 +42,20 @@ It can be a string-typed path (see above example), or a list of root directories
 ```javascript
 var engine = new Liquid({
     // relative paths will be resolved against `pwd`
-    root: ['views/', 'views/partials/']
+    root: ['views/', 'views/partials/'],
+    extname: '.liquid'
 });
 ```
 
+When `{% render "foo" %}` is renderd or `liquid.renderFile('foo')` is called, the following files will be looked up and the first existing file will be used (if none of them exists an `ENOENT` error will be throwed):
+
+- `pwd`/views/foo.liquid
+- `pwd`/views/partials/foo.liquid
+
+When LiquidJS is used in browser, say current location is `https://harttle.com/bar/index.html`, only the first `root` will be used and the file to be fetched is (if fetch fails an `ENOENT` error will be throwed):
+
+- `https://harttle.com/bar/foo.liquid`
+
 ## Abstract File System
 
 LiquidJS defines an abstract file system interface in [src/fs/ifs.ts][ifs] and the default implementation is [src/fs/node.ts][fs-node] for Node.js and [src/fs/browser.ts][fs-browser] for the browser bundle.