popsu-d7/sites/all/modules/skinr/help/features.html

<p><code>[features]</code> are an optional Skinr setting. They do not need to be
  specified. By default Skinr will assume that your styles can be used anywhere
  Skinr is available on your site, i.e. nodes, blocks, etc. If you want to
  reduce UI clutter and have more fine grained control over where your skins are
  used, you'll want to use the <code>[features]</code> option.
</p>
<p>The <code>[features]</code> setting is the equivalent of the high level
  Drupal theme hook. If nothing is specified in your skin it will appear
  everywhere by default. It may only contain underscores. By specifying a
  <code>[features]</code> you are telling Skinr: Only show this skin when
  editing X.
</p>
<p>Below is a listing of available options, by module:</p>

<h3>Blocks</h3>
<pre>
skinr[skin_system_name][features][] = block
skinr[skin_system_name][features][] = block_[module]
</pre>

<h3>Comments</h3>
<pre>
skinr[skin_system_name][features][] = comment_wrapper
skinr[skin_system_name][features][] = comment_wrapper_[node_type]
</pre>

<h3>Nodes</h3>
<pre>
skinr[skin_system_name][features][] = node
skinr[skin_system_name][features][] = node_[node_type]
</pre>
<em class="marker">Note: node_[node_type] is not yet implemented.</em>

<h3>Page (body classes)</h3>
<pre>
skinr[skin_system_name][features][] = page
</pre>

<h3>Panels</h3>
<pre>
skinr[skin_system_name][features][] = panels_pane
skinr[skin_system_name][features][] = panels_panel
</pre>

<h3>Views</h3>
<pre>
skinr[skin_system_name][features][] = views_view
skinr[skin_system_name][features][] = views_view__[style_name]
skinr[skin_system_name][features][] = views_view__[display_name]
skinr[skin_system_name][features][] = views_view__[view_name]
skinr[skin_system_name][features][] = views_view__[view_name]__[display_name]
</pre>
<em class="marker">Note: views_view__[style_name] is not yet implemented.</em>