This template doesn't show anything on its own, but it adds a cowboy face in the top right corner of the page. This cowboy emoji is from Google's Noto Sans Colored Emoji set as of August 26, 2017. This is the de facto logo used by RedWarn.
If the template is on a user page or user talk page, the category Category:Wikipedians who use RedWarn is added to the page.
Usage
To use this template, simply transclude it anywhere in your user page.
{{RedWarn topicon}}
You may choose to prevent your user page from being added to the category. In that case, you should supply the nocat parameter with any value similar to "yes". If you want to force the category on a page outside of the user space or user talk space, you can supply the nocat parameter with any value similar to "no".
{{RedWarn topicon|nocat=yes}} <!-- This will stop the category from being added, no matter what -->
{{RedWarn topicon|nocat=no}} <!-- This will add the category to the page, no matter what -->