Portable Web Documents (PWDs) are a technology developed by Polar that combines the benefits of PDFs and HTML content. While PDFs are great for static layouts and long-term preservation, they lack support for dynamic layouts, video, and interactive charts. On the other hand, HTML has these compelling features but is limited in terms of offline caching and censorship. PWDs solve these issues by bundling a full HTML document with all its dependent resources into a zip file archive. However, creating PWDs poses challenges such as capturing the original form and intent of web designers, deactivating scripts, and handling iframes. Despite current limitations, such as support for only static layouts and limited access to user cookies, Polar aims to enhance PWDs in the future with features like fully fluid layouts, caching of media, collaboration, and support for video and interactive charts.
https://getpolarized.io/2019/05/11/portable-web-documents.html