Request context: Loading SVG as background image from [[ https://commons.wikimedia.org/w/index.php?title=MediaWiki%3AGadget-EnhancedPOTY.css&type=revision&diff=191359963&oldid=114497048 | this CSS file ]].
GET /wikipedia/commons/c/c9/Ballot-sprite.svg HTTP/1.1
Host: upload.wikimedia.org
User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:45.0) Gecko/20100101 Firefox/45.0
**Accept: image/png,image/***;q=0.8,*/*;q=0.5
Accept-Language: de,en-US;q=0.7,en;q=0.3
Accept-Encoding: gzip, deflate, br
Referer: https://commons.wikimedia.org
Cookie: WMF-Last-Access=26-Mar-2016;<secret>
Connection: keep-alive
Pragma: no-cache
Cache-Control: no-cache
HTTP/1.1 200 OK
Date: Sat, 26 Mar 2016 22:43:24 GMT
**Content-Type: text/html**
Content-Length: 1029
x-object-meta-sha1base36: <some-stuff-i-cant-read>
Last-Modified: Sat, 26 Mar 2016 22:19:52 GMT
Etag: <more-stuff-i-cant-read>
X-Timestamp: 1459030791.20288
x-trans-id: <more-stuff-i-cant-read>
Content-Encoding: gzip
X-Varnish: <more-stuff-i-cant-read>
Via: 1.1 varnish, 1.1 varnish, 1.1 varnish
Accept-Ranges: bytes
Age: 1380
X-Cache: cp1050 miss(0), cp3049 hit(1), cp3039 frontend hit(13)
strict-transport-security: max-age=31536000
x-analytics: WMF-Last-Access=26-Mar-2016;https=1
x-client-ip: 217.186.201.91
access-control-allow-origin: *
access-control-expose-headers: Age, Date, Content-Length, Content-Range, X-Content-Duration, X-Cache, X-Varnish
Timing-Allow-Origin: *
X-Firefox-Spdy: 3.1
Expected: content-type: **image/svg+xml**
Therefore, I can't use uploaded SVGs as background images for POTY. Firefox simply doesn't display it.