The exact DR1 was "unreleased":
Youtube: Apple's Copland DR1 unreleased Mac OS prototype
Published on Apr 3, 2010
This is the never-released Copland OS (System 8) prototype from 1996, booting on a PowerMac 7600/66 AV. It boots to the "Z Theme"
In this video you can see the cool Mac OS logo fading in, and then a bunch of verbose messages as the hardware is examined and initialized.
The OS itself is very unstable and crashes very frequently -- this release was intended to help hardware vendors develop drivers for the future release, and came with software so that it could be debugged from a connected PC.
A more convincing demo from Apple is
Youtube: Mac OS 8 (code name Copland) Demos:
Published on Feb 15, 2014
June 28, 1996 - Demonstration of Apple Computer's operating system Mac OS 8 (code name Copland). Demos include:
Organizing information on the desktop.
A scalable user interface.
The computer as assistant.
QuickDraw 3D and QuckTime multimedia on the Internet.
An Exit button displayed in the lower left hand side corner of each demo is unrelated to Mac OS 8 (code name Copland).
As with the renaming conundrums, rebranding Mac OS 8 Copland by ripping out most of the stuff that would have made it "Copland", it gets difficult to ascertain at what stage the different available 'releaases' are.
However, Macintosh Repository offers abandonware download links for
Copland D9 (Copland Developer Release: Tools Edition)
Copland OS Beta (D7E1, D11E4 June Release, D11E4)
Mac OS 8.0 Beta "Copland"
Mac OS 8.0 Copland (Beta Builds)
And the fittingly named WinWorldPC offers
Apple Mac OS 8.0 ("Copland" 8.0.B5) (SIT)
Apple Mac OS 8.0 ("Copland" 8.0.D11E4) (SIT)
Apple Mac OS 8.0 ("Copland" 8.0.D7E1 A) (SIT)
Installation notes: There are no known emulators that will run MacOS 8 Copeland. To run it, you must install it on a supported Macintosh PowerPC computer.
You might have to look at the dates quite closely:
Apple finally decided to cancel Copland in May 1996.
And you might read more about D11E4, from Apple documents.
The links to these archives should be quite fine. Not only because they are only linking abandonware, and not everyone on this globe resides in preposterously restrictive jurisdictions, and it seems this was even distributed partially to the general public in 1996's Macworld.