Curate the tennis topic

[bensynapse]

Please confirm this pull request meets the following requirements:

• I followed the contributing guidelines: https://github.com/github/explore/blob/main/CONTRIBUTING.md.
• This change is not self-promotion.

Which change are you proposing?

• Suggesting edits to an existing topic or collection
• Curating a new topic or collection
• Something that does not neatly fit into the binary options above

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Editing an existing topic or collection

I'm suggesting these edits to an existing topic or collection:

• Image (and my file is *.png, square, dimensions 288x288, size <= 75 kB)
• Content (and my changes are in index.md)

Please replace this line with an explanation of why you think these changes should be made.

Curating a new topic or collection

• I've formatted my changes as a new folder directory, named for the topic or collection as it appears in the URL on GitHub (e.g. https://github.com/topics/[NAME] or https://github.com/collections/[NAME])
• My folder contains a *.png image (if applicable) and index.md
• All required fields in my index.md conform to the Style Guide and API docs: https://github.com/github/explore/tree/main/docs

The tennis topic is widely used (about 475 repositories tag it, plus related tags such as atp and wta), but https://github.com/topics/tennis currently has no curated content. This pull request adds a neutral, encyclopedic index.md with a short description, Wikipedia link, and related topics that are in active use (sports, atp, wta), so people browsing the topic get context about the sport and the kinds of projects tagged with it. No image is included because tennis is a sport with no official logo, per the style guide. Drafting was AI-assisted; I reviewed and revised the text and verified the facts and formatting against the contributing guidelines, style guide, and API docs.

Something that does not neatly fit into the binary options above

• My suggested edits are not about an existing topic or collection, or at least not a single one
• My suggested edits are not about curating a new topic or collection, or at least not a single one
• My suggested edits conform to the Style Guide and API docs: https://github.com/github/explore/tree/main/docs

Please replace this line with an explanation of your proposed changes.

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Please note: we will close your PR without comment if you do not check the boxes above and provide ALL requested information.

[github-actions]

Maintainer triage

Topics

• tennis — 475 repositories — topic page