The available attributes for an Axis object are listed in the docs now, e.g. ? Axis.
There is a slight difference between Block objects (previously called Layoutablels) and plot elements (or recipes). To get the attributes for a block you have to ask for the docs of the type, e.g. ? Axis, whereas for the latter you have to ask for the plotting function, e.g. ? lines.
To inspect and change attributes you can either pass a keyword argument or access them directly, e.g. axis.xlabel.