Thanks. I have moved the Mainpage back to mainspace, so now it looks ok. Atleast svwiki and sewiki are also using portal namespace for its main page, so I don't think its very uncommon.

Thanks for the documentation for how to disable this styling. I have added "theme-night-mainpage" to MediaWiki:Wikimedia-styles-exclude. The problem is still there though, but that is probably because of caching? I have made sure the front page should look ok if the caching caches up: User:Tholme/MainPage

In T211745#4816598, @Aklapper wrote:

It looks like the ImageMagick software supports conversion since version 7.0.7-22 if compiled with --with-libheif according to https://github.com/ImageMagick/ImageMagick/issues/507 . Also see https://photo.stackexchange.com/questions/91640/how-can-i-convert-an-apple-ios-heif-image-into-jpeg

According to https://packages.debian.org/search?keywords=ImageMagick , Debian (the distribution used on Wikimedia servers) only ships ImageMagick version 6.9.x which means this likely will not happen soon.

No, haven't noticed this lately either. Agree that this probably can be closed.

No disagreement regarding the wrong cites, but I'm not really sure what was intended here. I have also found several other errors of the same type. Seems like it still doing this: