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Nicolas Chevobbe

@nicolaschevobbe

Firefox DevTools engineer Skateboarder

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18.11.2024
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Latest posts by Nicolas Chevobbe @nicolaschevobbe

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What's My JND? Find your Just Noticeable Difference in colour perception. How small a colour difference can you actually see?

without cheating this time, but I took my time and moved my head a lot ^^

What's My JND? 0.0030
Can you beat it? www.keithcirkel.co.uk/whats-my-jnd...

10.03.2026 17:18 πŸ‘ 2 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0

opened RDM, set it to the narrowest possible value, clicked on the middle of the screen each time I couldn't see the limit ^^

10.03.2026 10:48 πŸ‘ 2 πŸ” 0 πŸ’¬ 1 πŸ“Œ 0
Abstract illustration of a CSS animation in the shape of a series of square that get incresingly rotated. The text reads: CSS animations as state machines.

Abstract illustration of a CSS animation in the shape of a series of square that get incresingly rotated. The text reads: CSS animations as state machines.

I feel like this is either very dumb or very clever. Either way, I blogged about it:

Using CSS animations as state machines to remember focus or hover states in CSS only.

patrickbrosset.com/articles/202...

09.03.2026 20:21 πŸ‘ 27 πŸ” 8 πŸ’¬ 3 πŸ“Œ 0

Nice post Patrick, that's pretty creative :)

There's a small typo (`But, CS animations`), and for the demo with the pseudo element you're talking about checkmarks but the demo displays (nice) cat emojis :)

10.03.2026 07:44 πŸ‘ 0 πŸ” 0 πŸ’¬ 1 πŸ“Œ 0
A graphic with the All Day Hey! logo at the top left, and conference information on the top right, reading:

"Thursday 7th May 2026
09:00 – 17:00 BST
Everyman Cinema
Leeds UK"

Below shows a Firefox logo which displays a swirl pattern alongside the word Firefox. Below that reads "Without our sponsors, there would be no conference. All Day Hey! is made possible by Firefox."

A graphic with the All Day Hey! logo at the top left, and conference information on the top right, reading: "Thursday 7th May 2026 09:00 – 17:00 BST Everyman Cinema Leeds UK" Below shows a Firefox logo which displays a swirl pattern alongside the word Firefox. Below that reads "Without our sponsors, there would be no conference. All Day Hey! is made possible by Firefox."

The mighty @webdevs.firefox.com are supporting All Day Hey! 2026. Without them, there would be no conference. @jakearchibald.com will be around on the day if you want to talk all things Mozilla!

Tickets and more information:
heypresents.com/conferences/...

04.03.2026 09:18 πŸ‘ 13 πŸ” 2 πŸ’¬ 0 πŸ“Œ 1
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CSS shape() landed in Firefox 148. It's similar to path(), but allows the full expressiveness of CSS…

02.03.2026 15:07 πŸ‘ 150 πŸ” 24 πŸ’¬ 8 πŸ“Œ 3
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You can throw away innerHTML and replace it with the new setHTML(), which has a built-in sanitizer. Here's how it works:

25.02.2026 12:09 πŸ‘ 155 πŸ” 25 πŸ’¬ 6 πŸ“Œ 7
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Igalia Coding Experience | Igalia - Open Source Consultancy and Development Igalia is an open source consulting firm specialised in the development of innovative projects and solutions. Our engineers have expertise in a wide range of technological areas, including browsers an...

If you're a student or early in your software/CS career, I encourage you to apply to the Igalia Coding Experience program. The deadline to apply is April 3.

People from underrepresented groups are encouraged to apply!

www.igalia.com/coding-exper...

24.02.2026 20:33 πŸ‘ 5 πŸ” 7 πŸ’¬ 0 πŸ“Œ 0
Gecko: Intent to ship: ariaNotify Gecko: Intent to ship: ariaNotify

Gecko: Intent to ship: ariaNotify

20.02.2026 03:36 πŸ‘ 14 πŸ” 9 πŸ’¬ 0 πŸ“Œ 0
2017167 - Using color picker after using Color vision simulation picks the wrong color NEW (nobody) in DevTools - Inspector. Last updated 2026-02-17.

Hello Ana, thanks for the report
We filed bugzilla.mozilla.org/show_bug.cgi... for this

17.02.2026 08:05 πŸ‘ 4 πŸ” 0 πŸ’¬ 1 πŸ“Œ 0
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HTML might be getting a new type of tag, which… hasn't happened this millennium. Here's the new syntax, and how it works:

16.02.2026 14:46 πŸ‘ 298 πŸ” 49 πŸ’¬ 14 πŸ“Œ 8
Contextually Styling Components Styling Design System Components depending on the context they find themselves in, as opposed to via props.

To celebrate my first merged PR into Firefox core, I wrote a too-long article on Contextual Design for (Opinionated) Component Libraries.

frehner.me/blog/context...

And it concludes with my reasons for submitting patches to Firefox and WebKit.

Lots of thanks to everyone who helped out, or

13.02.2026 22:08 πŸ‘ 28 πŸ” 5 πŸ’¬ 4 πŸ“Œ 0

Who should I speak to to get this t-shirt Jake?

12.02.2026 20:24 πŸ‘ 10 πŸ” 0 πŸ’¬ 1 πŸ“Œ 0

This was actually some of my first contributions to the area of web browsers, just finding and fixing errors in the support data. Normally just ones I stumbled across as a web developer too, rather than anything deliberate.

09.02.2026 06:33 πŸ‘ 9 πŸ” 2 πŸ’¬ 0 πŸ“Œ 0
A straight, orange and yellow old building with front covered with bricks. It has a lot of small windows that each are near each other in a stair pattern. A lot of different yet satisfying shapes next to each other near the top of the building. The front is half-covered with a warm afternoon winter light.

A straight, orange and yellow old building with front covered with bricks. It has a lot of small windows that each are near each other in a stair pattern. A lot of different yet satisfying shapes next to each other near the top of the building. The front is half-covered with a warm afternoon winter light.

Saw this building in Paris, last year. Super nice shapes #reference #environmentart

28.01.2026 22:46 πŸ‘ 28 πŸ” 2 πŸ’¬ 2 πŸ“Œ 0
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One more custom <select> demo, with a bunch of CSS transforms and animations.
I can't get enough of this. So cool.

27.01.2026 09:38 πŸ‘ 150 πŸ” 20 πŸ’¬ 1 πŸ“Œ 2
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View Transition Types are newly baseline! These make it easier to build transitions that are specific to particular situations.

Also, we have some new View Transition DevTools in Firefox 147…

19.01.2026 14:13 πŸ‘ 97 πŸ” 8 πŸ’¬ 2 πŸ“Œ 1
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Do not give up your brain It's tempting to just let tools think for you, but you still need to be able to think for yourself and stay sharp.

"Once men turned their thinking over to machines in the hope that this would set them free. But that only permitted other men with machines to enslave them."

― Frank Herbert, Dune

cassidoo.co/post/good-br...

17.01.2026 03:32 πŸ‘ 215 πŸ” 49 πŸ’¬ 8 πŸ“Œ 1
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The Navigation API is newly baseline! The web now has sensible, low-level routing for navigations.

15.01.2026 15:25 πŸ‘ 164 πŸ” 29 πŸ’¬ 9 πŸ“Œ 5
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CSS anchor positioning is newly baseline! This opens the door for lots of new creative CSS.

It's a huge feature, but here are the basics.

13.01.2026 16:09 πŸ‘ 209 πŸ” 39 πŸ’¬ 9 πŸ“Œ 11
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fqueze - Overview fqueze has 35 repositories available. Follow their code on GitHub.

I only reviewed the patch, github.com/fqueze wrote the feature πŸ™‚

12.01.2026 07:17 πŸ‘ 1 πŸ” 0 πŸ’¬ 1 πŸ“Œ 0
a soft hill with a ray of golden light shining on it
there's a small house and a tree at its foot

a soft hill with a ray of golden light shining on it there's a small house and a tree at its foot

Golden light study

I still haven't found who is the photographer that took the ref picture :/

11.11.2025 10:37 πŸ‘ 209 πŸ” 50 πŸ’¬ 2 πŸ“Œ 0

Ah yeah, that's this one, I mixed it up

24.12.2025 17:39 πŸ‘ 1 πŸ” 0 πŸ’¬ 1 πŸ“Œ 0

That's exactly what's planned, do the same thing as WebMidi
There was an intent to prototype sent last week πŸ™‚

24.12.2025 16:12 πŸ‘ 2 πŸ” 0 πŸ’¬ 1 πŸ“Œ 0

Neither is herpes, but I’ll keep doing my work without either.

21.12.2025 14:22 πŸ‘ 4408 πŸ” 730 πŸ’¬ 52 πŸ“Œ 17

and surprisingly not super easy to get right! There's so much that you have to think of when you do this, I should write a small blog post about it

12.12.2025 15:32 πŸ‘ 1 πŸ” 0 πŸ’¬ 1 πŸ“Œ 0
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In Firefox 146 DevTools, long lists of unused CSS custom properties collapse, decluttering the UI, and improving performance

12.12.2025 09:50 πŸ‘ 54 πŸ” 5 πŸ’¬ 1 πŸ“Œ 1
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Firefox 146 release notes for developers (Stable) - Mozilla | MDN This article provides information about the changes in Firefox 146 that affect developers. Firefox 146 was released on December 9, 2025.

A bunch of web platform features and bug fixes landed in Firefox 146. There'll be more videos about the highlights soon, but in the meantime, here's a summary: https://developer.mozilla.org/en-US/docs/Mozilla/Firefox/Releases/146

10.12.2025 11:56 πŸ‘ 27 πŸ” 4 πŸ’¬ 0 πŸ“Œ 1
Me smiling at the camera, sit on a red office chair, with my young cat wrapped around my neck, also looking at the camera

Me smiling at the camera, sit on a red office chair, with my young cat wrapped around my neck, also looking at the camera

It's been 10 years since my first patch landed on the #Firefox repo: hg-edge.mozilla.org/mozilla-cent... πŸŽ‚

Here's a picture of me at that time, with my beloved assistant

10.12.2025 10:05 πŸ‘ 11 πŸ” 0 πŸ’¬ 1 πŸ“Œ 0