The explanatory text for these: "Learn how to blahdy blah" doesn't add anything to the titles. If they're worth having, they should help people understand what's in there as a very short abstract. For example:

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Getting Started

How to contribute code to the SDK: finding the code, assigning yourself a bug, getting patches reviewed, and getting help.

Classes and Inheritance

How classical inheritance can be implemented in JavaScript using constructors and prototypes, and
the functions the SDK provides to simplify this.

Content Processes

The SDK was designed to work in an architecture where the code to handle web content runs in a separate process from the privileged add-on code. This article covers the main features of that design.

Private Properties

Different ways to implement private properties in JavaScript - prefixes, closures, weakmaps, and namespaces - and how private properties are supported in the SDK.

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We could maybe do better than these, but I think they're more helpful.