It seems like this leak of Android 4.3 Jelly Bean with Sense 5.0 for the AT&T HTC One is working without problems.
If we were to listen to all speculation that is currently spread across Android community threads, this leak very close to the final OTA Update, which should be available soon for all AT&T HTC One devices across US. This is great news for all users who own an HTC One from AT&T.
AT&T HTC One is expected to get the firmware update to Android 4.3 later this month or early October. This leaked version of Android 4.3 RUU with Sense 5.0 RUU has been compiled by Birdman from RootzWiki. This firmware leak update is stock Android 4.3, it is not deodexed and no bloatware has been removed before release.
The RUU description means ROM Update Utility. This usually comprises the latest firmware build and it means that AT&T only has to give the go ahead for the OTA Update to be pushed out for HTC One devices. If this smartphone will get the update to Android 4.3 it will become the first device to receive it after the Google Nexus 4.
The Sense 5.0 is the same as the older versions but with several tweaks and stability improvements added. There is no official word on any new Sense 5.x versions, but we should get more info when HTC will launch their new phablet device.
Another device that will feature Android 4.3 soon is most probably the Samsung Galaxy Note 3.
If you want to flash this leaked update file on your AT&T HTC One, then you should head to RootzWiki forum thread here. You can flash the complete RUU zip or you can choose to flash the ROM and radio files one by one. Remember that by using these custom methods to flash an update you risk bricking your device, which is why it would be best for you to wait for AT&T to release the official Android 4.3 OTA for your HTC One device.