I don't know. The wiki is hosted by Weird Gloop, not me.

There is already a "Show Preview" button. Why is yet another button needed?

The button would do the change the wikitext to what it is after saving.

I don't see why MediaWiki should support editing content of some Template page within a completely different page.

I didn't mean that it would change the template itself. I meant that if you want to substitute a template and make a small change to the substituted content.

Let's say we have a template {{Hello}} with content "Hello {{{1}}}!".
Then I'm making a page and I write the following:

{{subst:Hello|hdicu}}

Then if I click the button, it would change the text I wrote to:

Hello hdicu!

For example if I wanted to change Hello to Hi without the button, I'd have to either copy contents of Hello template to the editor and replace {{{params}}} with right values or save the page in order to change it.

I don't think people are using @ in links to mainspace pages

@Aklapper You should be able to click the {{/Indev}} part that would lead you to the /Indev subpage. I tried to upload it here but I was told the file was too big.

The URL after replying was https://minecraft.wiki/w/Minecraft_Wiki_talk:Community_portal?curid=2925&diff=0#I_have_a_very_very_bad_problem.
There was following error in DevTools after posting it:

In wikitext diff
Example link
Video

I think that it should be there because if you look recent changes and see that someone made a change to some file description, it would be helpful to see what file is it without needing to click "read" and then losing the diff.

I think that you should be able to transclude any page. It does not make sense that transcluding some pages output a link instead of the list. You can always use [[Special:WantedCategories]] to make a link so it's very weird that when trying to transclude some pages (I found same problem with Special:Log) it outputs a link there. No one would expect that transcluding makes a link. I think that transcluding should NEVER make a link (unless the transcluded page contains that link or if transcluding wouldn't work for some reason with that page)

I know, you told that earlier and I got following response when I asked

They spam it and make it harder to view actual results. See for example this. Most of them are from user pages and you can do nothing for them

Yes, after looking special:version I found that it was an extension. Sorry for needless report.

Some design for how the filters should look. Tabs? A search form? A drop down? Is this covered in the UI standards spec?

I'm using Edge on Mac
Screenshots from devtools:
After trying to click button