Você deve verificar o Zeal , ele é um navegador de documentação off-line para desenvolvedores de software.
Aqui está uma captura de tela:
Outraopçãoaconsideraré
DevDocs combines multiple API documentations in a fast, organized, and searchable interface.
E, finalmente, você pode conferir DevHelp :
Devhelp is a developer tool for browsing and searching API documentation.
It provides an easy way to navigate through libraries and to search by function, struct, or macro.
The documentation must be installed locally, so an internet connection is not needed to use Devhelp.
Devhelp works natively with GTK-Doc, so the GTK+ and GNOME libraries are well supported. But other development platforms can be supported as well, as long as the API documentation is available in HTML and a *.devhelp2 index file is generated (see the README file for more information).
Devhelp integrates with other applications such as Glade, Builder or Anjuta, and plugins are available for different text editors (gedit, Vim, Emacs, Geany, …), see the plugins directory.
Espero que ajude.