Something is Odd About MDN These Days - And Googles AI is Gaslighting me About it...

I went to MDN today and thought "something is odd about the font...".
So I went to google and asked: "did they change the font on mozilla developer network".

But Googles AI said:

No, Mozilla Developer Network (MDN) hasn't changed its font; any perceived changes are likely due to your browser's font rendering, the specific fonts used on a page, or a local Firefox update affecting font handling, rather than a change on the MDN website itself. To change the fonts you see, you can adjust the font settings in your Firefox browser's preferences under the "Language and Appearance" section.

I revisited MDN, spun up the devtools... and I never heard about the "JetBrains Mono" font.

Maybe it was always there, and it was not installed on my machine. When did I install it? I don't know. Am I crazy? (What about my Phone? Web-Fonts?)

Before completely losing my mind I rephrased my question:

"did they change the mdn font"

Yes, the MDN Web Docs site launched a significant front-end redesign in August 2025 that included improved typography for readability, along with a new code font for better code rendering across platforms, and updated icons and search features.

Well...

I should disable those AI responses - or find an extension that does it.

Here is the Article on MDN about the redesign: Launching MDN's new front end