It seems Apple has made the prerelease Configuration Profile Key Reference available to the public. This the technical documentation for much of the iOS and Mac enterprise management capabilities Apple makes available via MDM vendors, Configurator, etc. (The other main document, the MDM Protocol Reference, remains behind the developer site authentication wall.)
Most of what we think of as “part of MDM” is really just the configuration settings that MDM can push out. This reference (expanded last year to include OS X) includes all the publicly known settings that can be configured via a profile. These profiles can then be installed on a device via USB, HTTP, or MDM.
The linked article includes a preliminary list of new changes, but as noted, we are still early in the beta process and all this could change before iOS 8 is released this fall.
The full Configuration Profile Key Reference (pre-release) is available here.