GET to list all files for the specified product...
/api/v2/products/:sku/files /api/v2/products/:sku/files.xml
Example result...
<?xml version="1.0" encoding="UTF-8"?>
<files type="array">
<file>
<id>123</id>
<filename>Part1.zip</filename>
<size_bytes type="integer">9774173559</size_bytes>
<content_type>binary/octet-stream</content_type>
<permalink href="http://demo.fetchapp.com/permalink/yuurud">/permalink/yuurud</permalink>
<url nil="true"></url>
</file>
<file>
<id>432</id>
<filename>External File Name</filename>
<size_bytes nil="true"></size_bytes>
<content_type nil="true"></content_type>
<permalink href="http://demo.fetchapp.com/permalink/werwa">/permalink/werwa</permalink>
<url>http://your.cdn.com/link/to/file</url>
</file>
</files>
For files stored in FetchApp, the url will be nil. For files stored externally the size_bytesand content_type will be nil since this information isn't available.