Extremely simple tool for WordPress owners: it tests if your site has the XML-RPC protocol still activated (yes by default in current installations).
It is beyond this site to debate why if should be disabled, unless an old compatibility is required, and bare the risk of remote attacks.
Privacy: we have no feedback of potential problem with this tool and author. But like many online services, you are here providing them with your own data. Depending of the criticity of your data, this is your responsibility to assess author's reputation and potential misusage, and to check and accept their terms and conditions, or not.
EN 
FR 
DE 
ES 
IT