I've just uploaded [[ https://commons.wikimedia.org/wiki/File:BSicon_RACONTgq.svg | File:BSicon RACONTgq.svg ]]. The colours I've used are F00 and FF0, which should be interpreted as FF0000 and FFFF00, but librsvg colours them differently. Even more confusingly, [[ https://commons.wikimedia.org/wiki/File:BSicon_RAl.svg | File:BSicon RAl.svg ]] uses the six-digit colours, but the rendering still uses the incorrect colours, and only in Firefox 57 and not in Tor Browser (Firefox 52 ESR) or Safari 11.
Or this is because librsvg changes all RGBs for whatever reason, and older files haven't been updated for this. The below file description pages look identical on Tor Browser and Safari but don't on Firefox 57 (I cleared my cache twice and it persists).
| BSicon RAr (2017) | BSicon AKRZrf (2011)
| {F10880613} | {F10880668}