Rails View Annotator

The Rails View Annotator wraps the rendering of Rails partials with html comments indicating the disk location of the rendered partial.

Simply add the gem to your Gemfile's development block.

group :development do
  gem 'rails_view_annotator'
end

Now rendered content will have instructive comments.

<!-- begin: app/views/user/_bio.html.haml (from app/views/user/show.html.haml:4) -->
<div class='bio'>Ed's Bio</div>
<!-- end: app/views/user/_bio.html.haml (from app/views/user/show.html.haml:4) -->

WTFPL