Okay, I need to create a Wikipedia-style document about the GNU GPL under the given categories. Let me start by understanding the requirements.

First, the structure needs an H1 title, an overview section, several H2 and H3 sections, and maybe references or related documents. The content should be accurate, objective, detailed but not too shallow, easy to read, and use technical terms with explanations. Also, markdown formatting is required with proper headings, lists, tables, code blocks if needed.

The main topic is GNU GPL under Technology > Software > License. So I need to cover what the GNU GPL is, its history, key features, differences from other licenses, usage examples, and maybe a comparison table.

Starting with the title: "GNU GPL" as H1. Then an overview section explaining what it is, its purpose, and significance. Next sections could be History, Key Features, Differences from Other Licenses, Usage Examples, and References.

For the history part, I should mention Richard Stallman and the Free Software Foundation, when it was created (1989), and major versions like GPL v2 and v3.

Key features would include copyleft, requirements for distribution, modification, and source code availability. Also, the concept of "viral" nature where derivative works must also be under GPL.

Differences from other licenses: Compare with MIT, Apache, BSD. Highlight copyleft vs permissive licenses. Maybe a table here to show differences in terms of restrictions, attribution, patent grants, etc.

Usage examples could include Linux kernel as an example of GPL-licensed software. Also mention how companies use it and the implications for developers.

Need to ensure that technical terms like "copyleft" are explained. For instance, copyleft is a play on "copyright," meaning that derivative works must also be under the same license.

Check if there's any important information I'm missing. Maybe include the GPL v3 changes, such as addressing software patents and digital rights management (DRM). Also mention the GNU Project itself.

Make sure to avoid markdown in the thinking process but structure it properly in the final answer. Use H2 for main sections, H3 for subsections if needed. Include a references section with links to official sources like the FSF website.

Check the length: need at least 800 characters. The example provided earlier is around that, so I should expand where necessary. Maybe add more details on each section, examples of companies or projects using GPL, and perhaps some common misconceptions.

Also, ensure that the language is clear and concise, avoiding jargon without explanation. For instance, when talking about "source code," clarify it's the human-readable form of the software.

Double-check facts: GNU GPL was first released in 1989, v2 in 1991, v3 in 2007. The Free Software Foundation is the organization behind it. Linux kernel uses GPLv2, but some parts are under different licenses.

Include a code block example of the GPL license text? Maybe not necessary unless required. Alternatively, mention that the full text is available on their website.

Finally, ensure all sections flow logically and cover the essential aspects without being too verbose. Keep paragraphs short for readability.