Another way to disable animations is to create ui.prefersReducedMotion (Number) with value 1 in about:config.

Does it still happen in Troubleshoot Mode?

You can right-click and select "Inspect" to open the built-in Inspector with this element selected.

• https://firefox-source-docs.mozilla.org/devtools-user/page_inspector/how_to/open_the_inspector/
• https://firefox-source-docs.mozilla.org/devtools-user/page_inspector/how_to/examine_and_edit_html/

You can check in the Rules tab in the right panel in the Inspector what font-family is used for selected text. You can check in the Fonts tab in the right panel in the Inspector what font is actually used because Firefox might be using a different font than specified by the website. If the Fonts tab is hidden, click the Down arrow at the right end.

• https://firefox-source-docs.mozilla.org/devtools-user/page_inspector/how_to/edit_fonts/

Via inspect element: when the windows animations are off it's using Times New Roman on the 'quote tweets' text and Segoe UI on the main tweet text, but with the animations on it's using 'TwitterChirp'. This persists in Troubleshoot Mode

I have the Control Panel For Twitter extension which is likely causing the Quote Tweets box to show a different font from the rest. I have disable this extension and it persists

I've also updated to Firefox 125.0.2

The animations I want disabled on Windows but enabled on Firefox for smooth scrolling

It always uses Noto Sans for me, regardless of the animation setting.

You can enable animations by creating ui.prefersReducedMotion (Number) with value 0 in about:config.