On other wikis as well, yes (I’ve noticed it from mine).

As you can see https://publictestwiki.com/wiki/SVG_test no SVG thumbnails are being created.

Same error with most of files here:
https://commons.wikimedia.org/wiki/Category:Antu_icons

No width and height specified as well (only viewbox) and they show up as text in full view on Commons.

This is really a bigger problem. Is there a way to display PNG thumbnails instead of SVG links on Miraheze? These files all return in plain/text content type, and while SVG converter from Commons converts them correctly into PNG thumbnails, Miraheze displays all SVG files as SVG files, so if file has incorrect content type, it isn't showing at all.

Either there is a need to have SVG conversion (at least to show PNG thumbnails from Commons) or some kind of mechanism for converting plain/text files to SVG content type. It is incorrect, however, to talk about SVG thumbnails, since it is just resized SVG files which are not loading correctly.

Since it seems to be a problem with this extension: https://github.com/p12tic/NativeSvgHandler

The weird thing is that it is not ALL SVG files, as a random one I found, https://meta.miraheze.org/wiki/File:Endomembrane_system_diagram_en.svg works perfectly fine. It is possible that there is an issue with that extension. I will investigate and make an issue there.

Do you have any other SVG->PNG conversion extensions/systems in mind?

In T1867#34892, @Reception123 wrote:

The weird thing is that it is not ALL SVG files, as a random one I found, https://meta.miraheze.org/wiki/File:Endomembrane_system_diagram_en.svg works perfectly fine. It is possible that there is an issue with that extension. I will investigate and make an issue there.

They have correct MIME type, so this is why other files are fine for that NativeSvgHandler extension. These icons do not.

https://github.com/p12tic/NativeSvgHandler/issues/9

There hasn't been a reply to the other issue, since November 2016, so maybe we should look into alternatives?

Or maybe fork it? There doesn't seem to be like this extension has any alternatives.

Also, just to check with you on some terminology: SVG is short for Scalable Vector Graphics. Maybe I was saying something wrong to you, but this extension does not create SVG thumbnails, since it does not need them (since it is scalable file), it is displaying full SVG files instead of PNG thumbnails created by MediaWiki by default. It is to reduce bandwidth from all the PNG thumbnails, I guess.

I think that it is good to use SVGs, but this issue with incorrect MIME type still needs to be solved in some way.

OK.

Even if we fork it, what fix could we apply in order for MIME files to work? (question to you and other sysadmins)

Same problem with https://commons.wikimedia.org/wiki/File:Breezeicons-status-24-dialog-information.svg and a bunch of different files from Breeze 5.22.0 categories - they are in HTML format for some reason and can't be loaded on Miraheze. Seems like it is better to resume PNG thumbnails rather than support NativeSvgHandler.

Testing page: https://commons.wikimedia.org/wiki/Breeze_5.22.0

@Lev Sorry for the late reply, but would you like NativeSvgHandler disabled on your wiki?

Forgot about this: yes, it is probably helpful to add a config option to disable it for people that encounter this problem in future (I have decided to not use those icons right now, but I would like the setting to be disabled).