
Description: Sioyek is an open-source PDF viewer designed for reading scientific papers and academic journals. It provides advanced PDF features like synchronized dual-page view, sticky notes, highlights and annotations. Sioyek aims to offer a clutter-free interface for focused reading.
Type: Open Source Test Automation Framework
Founded: 2011
Primary Use: Mobile app testing automation
Supported Platforms: iOS, Android, Windows

Description: STDU Viewer is a free portable software used to open and view various file types like PDFs, images, Microsoft Office documents, emails, archives, EPUB books and more. It supports viewing over 20 file formats and includes features like tabbed browsing, thumbnail previews, bookmarks and annotations.
Type: Cloud-based Test Automation Platform
Founded: 2015
Primary Use: Web, mobile, and API testing
Supported Platforms: Web, iOS, Android, API