This is the API documentation for each class in xibless. Classes in the API documentation contain methods, which can of course be called, but they also contain attributes (such as x, y, font, etc.). These can be set directly in this fashion:
button.x = 42
How to read the API. Being a wrapper around Cocoa, there are naturally a lot of attribute names that are similar to their Cocoa counterpart. When a class has an attribute that doesn’t specify what attribute it wraps in Cocoa, you can assume that it wraps an attribute with the exact same name.