Contains pure-function utilities for HTML cleaning and formatting: _formatHtml performs recursive whitelist-based tag filtering and attribute normalization, _clearMsWord strips Microsoft Word cruft (styles, comments, invalid markup), and _formatUrl resolves relative to absolute URLs or applies protocol prefixes. These functions operate on raw HTML strings without DOM dependencies, making them directly extractable into any JavaScript project needing robust HTML sanitization.

Implements KRange, an independent wrapper around DOM Range/Selection that normalizes cross-browser differences. Provides methods for selecting nodes, collapsing, enclosing, extracting contents, and creating bookmarks (serializable markers for undo/redo). The class is self-contained and thoroughly unit-tested (over 200 assertions), demonstrating careful boundary coverage. Can be extracted as a shared DOM range utility for rich text applications.

Defines KUploadButton, a reusable widget that handles file uploads using a transparent iframe fallback for browsers without XMLHttpRequest Level 2 support. Encapsulates form construction, iframe communication, progress simulation, and callback management. The component depends only on KWidget and KNode (both internal but structurally simple) and can be repurposed as a standalone upload button for legacy file upload scenarios.