d2wy8f7a9ursnm.cloudfront.netは安全ですか？

It depends on what script are you requesting. For instance i use bugsnag, wich use this server //d2wy8f7a9ursnm.cloudfront.net/bugsnag-3.min.js, en this scripts sends report on any crash or js error on bugsnag servers. This is usefull to debug your aplication. I've observed behavior of this script and really it sends data only if there any error so its ok.

Noticed this domain on NoScript when using DiscordAttempting to navigate to the page es the following XML code: <Error><Code>AccessDenied</Code><Message>Access Denied</Message><RequestId>95041DDC43C5CD1F</RequestId><HostId>LR9IGQsSGk25Y12NjQ88fJHoBOk2ONkfxj/e9alt0NU/E4P5+9mmHg1+mNrpC/PoyIY4Nk1e0cw=</HostId></Error> hpHosts has classified it as and Ad/Tracking Server, and since Discord is still in beta it's likely a debugging usage tracker. Have not seen any ads due to it yet, but I would like to hear or see more info about this either on the site or from the developer before I'd be willing to trust it.