Follow up: interestingly the main concern seems to be it effecting the Monobook skin.

I personally think we should revisit applying MediaWiki UI to all skins especially monobook. I know there has been concern about it raised in bugs by Isarra and others. I'm not sure why that decision was made but I personally feel like it is a bad one.

On 9 Oct 2014 16:39, "Jon Robson" <jrobson@wikimedia.org> wrote:
Thanks to Lego this conversation was brought to my attention.
Basically a mediawiki ui progressive button sneaked into the special
contributions page. Although not a big deal (in my opinion) this has
caused a tiny bit of a stir as might be expected (Facebookization) and
gives us a useful insight into how any form changes might be
perceived.

This button is no longer blue on mediawiki.org and will go back to
normal styling on next deploy. It seems silly to lightning deploy a
fix for this in my opinion.

Read more here:
https://en.wikipedia.org/wiki/Wikipedia:Village_pump_%28technical%29#Enormous_blue_search_button

I've replied, feel free to do so also.

What happened:
* https://gerrit.wikimedia.org/r/#/c/162121/ got deployed.
* This patch https://gerrit.wikimedia.org/r/#/c/163775/ did not.