Clacks Overhead - GNU Terry Pratchett

Name: Clacks Overhead - GNU Terry Pratchett
Rating: 4.88 (163 reviews)
Author: Peter Bell

GNU Terry Pratchett. Show user when 'Clacks-Overhead' appears in HTTP headers.

As of May 2026, Clacks Overhead - GNU Terry Pratchett has 6,000 users and a 4.88/5 rating from 163 reviews in the fun category.

Peter Bell fun★ Featured

Chrome Web Store ↗.crx

Users−14.3%

6.0K

6,000

Rating0%

4.88

163 reviews

Reviews0%

163

Version

3.0

Manifest V3

90-day change · In the last 90 days this extension lost 1.0K users.

History

1 snapshots

Tracking since Apr 24, 2026.

View as table

Date	Users	Rating	Reviews	Version
Apr 24, 2026	7.0K	4.88	163	3.0
Now	6.0K	4.88	163	3.0

Permissions & access

Permissions: activeTabwebNavigationwebRequest
Host access: https://*/*, http://*/*

Screenshots

Clacks Overhead - GNU Terry Pratchett screenshot 1

Clacks Overhead - GNU Terry Pratchett screenshot 2

About

This extension is a tribute to the late Terry Pratchett (https://en.wikipedia.org/wiki/Terry_Pratchett). It displays an icon when the user visits a website sending a "Clacks Overhead" message. If the user clicks on the icon, it will display the message and animated clacks semaphore code.

More information can be found here: http://www.gnuterrypratchett.com/

Notes: 
1. This extension does not collect any data or send any information anywhere.
2. All code is open source on Github: https://github.com/newfolder0/chrome-clacks

Contributors:
- Peter Bell (original author)
- Charlie Wheeler-Robinson (bug hunting, refactoring, improving in early versions)
- Jimmy Nyström (code)
- Melanie Wilberforce (icons)
- Rob Grundy (who made the Firefox extension) for sending me the clacks icons used in the animation
- Backspindle Games for producing the clacks icons in the animation
- Sap1ens, jwakely, and Amy Atha-Nicholls (generously offering new icons)
- yousuf811 on Github (squashing bugs)
- Jarek Glowacki for some CSS help
- Jake Heimark (hmk on GitHub) for fixing the manifest and keeping this extension alive in 2024
-See GitHub issues and pull requests for others