Update: Microsoft's Brandon LeBlanc directly contacted the team managing this part of the operating system and found out that this is an older version of the new Bluetooth page that is begin worked on. It was already present in older Insider builds like 14955 but it was hidden from consumers because of the unfinished state. According to Brandon, this change isn't coming in an upcoming build. Original story below.
I know. Not sure where he dug it up but the team who owns that settings page tell me its not something that's coming.
— Brandon LeBlanc (@brandonleblanc) November 11, 2016
Microsoft has been working on unifying their operating systems into one since the migration from a Windows CE kernel in Windows Phone 7 to the newer Windows NT in Windows Phone 8. The progress of the project today is what Windows 10 has become.
However, as the migration isn't as simple as one might think, some legacy code still remains on platforms like Xbox or phones. One of these parts of the code is the Bluetooth settings page, with multiple others like "Extras" and the network settings page, which recently got updated featuring the same underlying code as its desktop counterpart.
The Bluetooth settings page that mobile fans of Microsoft's operating system are currently "enjoying" is just a reskinned and poorly ported version from Windows 10 Mobile's predecessor. This may change in the near future as come new information has been leaked onto the web, disclosing three screenshots of a Windows 10 Mobile-powered system. The new page seems to be powered by the same code that the desktop version uses, which means that it could get bugfixes and general support a lot faster in the future, as Microsoft's polish on their main Windows 10 version would transfer over to mobile.
— Gustave Monce (@gus33000) November 11, 2016
The new page may be released as early as the next Fast Ring Build, judging by the speed of internal builds reaching us. When the time comes, many Windows 10 Mobile users will be happy with the change because what's offered right now is far from an optimal experience.