Dash is a great tool for reading documentation offline of your favorite framework or library. You can also generate your own docsets and host them as feeds so anyone can use it. I have found an open source iOS project on github (https://github.com/omz/DocSets-for-iOS) for reading the mac os x / iOS docsets which is a bit dated but have not been able to find any project that’s compatible with Dash docsets in general. Maybe a side project?