DevDocs combines multiple developer documentations in a clean and organized web UI with instant search, offline support, mobile version, dark theme, keyboard shortcuts, and more.
DevDocs vs Devhelp opinions
Open source, nice interface with dark variant, offline documentation, good search engine and many languages documentation.
Zeal is a simple offline API documentation browser inspired by Dash (OS X app), available for Linux and Windows.Discontinued
The last version (0.6.1) is from October 2018.
Dash is an API Documentation Browser and Code Snippet Manager. Dash stores snippets of code and instantly searches offline documentation sets for almost any API you might use. You can even generate your own docsets or request docsets to be included.
Offline search tool for developers. Find what you need without the need for Internet access.Discontinued
The project is no longer maintaned since May 2016. Last version, 0.1.1, released in March 2016, can be still downloaded from GitHub.