This flag, as well as other fake sports flags, is fictitious and is useful only to facilitate visual identification of some articles within Wikipedia. This flag has some visual elements that are similar to official logos or coats of arms of certain clubs, such as colors or some symbol, but they are NOT official and don't have any direct relation to the crest, symbol or official flag of the club. Thus, even if you consider this symbol to be reminiscent of some elements of the club, this image does NOT correspond, and is not even similar to the official symbol.

Official symbols must not exist in Commons because they are protected by authorial rights (copyright); in this way, if you want to localize the club's symbol, crest or official flag, try to make contact with the club: ask for the official symbol and a possible license of use for your purpose.