
Description: Skim is a PDF reader and note-taking application for macOS. It provides annotations, highlighting, and notation tools for PDF documents, allowing users to mark up PDFs. Skim also enables searching PDF documents and works well with large PDF files.
Type: Open Source Test Automation Framework
Founded: 2011
Primary Use: Mobile app testing automation
Supported Platforms: iOS, Android, Windows

Description: Xournal++ is a free, open-source notetaking and sketching software for Linux. It supports pen input and annotations on PDFs. Key features include sticky notes, rulers, page templates, shape recognition, and LaTeX support.
Type: Cloud-based Test Automation Platform
Founded: 2015
Primary Use: Web, mobile, and API testing
Supported Platforms: Web, iOS, Android, API