Kind of seems like you're trolling here but in case you're serious - it's odd to quote the middle of the docs and then complain that knowing nothing about the space you don't understand a given line.
Did you try the first sentence?
> Native Navigation is a navigation library for the React Native platform.
There you go, that's what it is.
If you don't have this problem and/or don't work on React Native apps, move on. If you're trying to learn and don't know what problems a navigation library solves, or don't know what view controllers in iOS development are, or don't know what redux is, or something else in the line you posted, try googling it and then looking at the examples in the library.
Did you try the first sentence?
> Native Navigation is a navigation library for the React Native platform.
There you go, that's what it is.
If you don't have this problem and/or don't work on React Native apps, move on. If you're trying to learn and don't know what problems a navigation library solves, or don't know what view controllers in iOS development are, or don't know what redux is, or something else in the line you posted, try googling it and then looking at the examples in the library.