Change loading animation

[Canapin (Coin-coin le Canapin)]

There are old discussions about this topic

Introducing Discourse Splash - A visual preloader displayed while site assets load

The splash lives in a different CSS scope, so sadly, you won’t be able to modify the CSS via themes. That said, we do have planned improvements, and I started with this one. Once the change is live on your site, the splash dots will use the colors from your current theme.

How to change Discourse splash animation?

That’s correct The splash loads before any core JS/CSS. The current implementation doesn’t focus on customization, but v2 will. The plan is to serve the splash image from localStorage for slightly increased performance and since it allows admins to set something custom via an inline <script> tag in the theme head_tag field. There’s currently no ETA for this work, and it needs a bit of testing, but it’s planned.

I don’t know if anything was done in the end to make modifications easy, and I don’t recall any topic featuring a custom splash.