Oxygen is an XML editor that provides a suite of XML authoring and development tools. It is designed to accommodate a large number of users, ranging from beginners to XML experts. It is available on multiple platforms, all major operating systems, and as a standalone application or an Eclipse plug-in. You can use Oxygen XML Editor in conjunction with all XML-based technologies and it includes a variety of tools for creating, editing, and publishing XML documents.
Source: https://www.oxygenxml.com