Digital Text Editing

TEI XML is a plain text format which can be edited by most code editors. Oxygen XML Editor, which many campuses license (including Notre Dame), has built-in support for XML and TEI validation, and it can perform functions like XSL transformations, which enable editors to convert XML into HTML, plain text, PDF, and so on. The downside is that Oxygen is a commercial product, and can be pricey if you don't have institutional support (check for academic versions).