How to read blender API manual? I can't understand some type definitions like


  bones
  Type:   ArmatureBones bpy_prop_collection of Bone, (readonly)


link: 
https://docs.blender.org/api/current/bpy.types.Armature.html#bpy.types.Armature.bones

What is this type?  Type should be simply one word. Why this one? 


  ArmatureBones bpy_prop_collection of Bone


We suppose to get data based on the reference section like this one, but I can't find bpy.context.armature. 

Can you shed a light one this? 


  C.armature


Traceback (most recent call last):
File "&lt;blender_console&gt;", line 1, in &lt;module&gt;
AttributeError: 'Context' object has no attribute 'armature'




Here are some variables also shown in manual, but I can't get them from my context. I find difficult to understand this manual. I want to show you, but
(I can't pose another picture. " You need at least 10 reputation to post more than 2 links?!" I just want to add another picture). 
Anyway it is listed in the manual as:

bpy.context.bone

Type:   bpy.types.Bone

bpy.context.edit_bone

Type:   bpy.types.EditBone

bpy.context.pose_bone

Type:   bpy.types.PoseBone

It comes out that I can't find C.bone or C.pose_bone in console.
Then why are they listed in this manual?
Don't worry, learning to read an API is a skillset unto itself, and a non-trivial endeavor at that, so it's okay for it to feel daunting. Unfortunately, it's usually necessary.

To answer your first question, ArmatureBones is a member of armature. It is a container, but it's not a built in Python container like list or tuple. It's a Blender container of type bpy_prop_collection, and this instance of that type of container contains Bones.

This would be roughly equivalent to saying "Encyclopedia is list of Books."

To answer your second question, there are a number of different types of context. Without knowing which one you're referencing it's hard to guess. However, there is a screen context, and it makes sense that a screen doesn't have an armature. So if you're referencing one of those other contexts, it'd make sense for it to has no attribute 'armature'.

Furthermore, the context that does have an armature is the buttons context, which means it's probably not the armature you're looking for. I suspect that you're actually after bpy.data.objects["name_of_your_rig"].data as referenced in this answer over here.

I hope that helps!