When CTP 2 was released for 6, Joe dedicated a brief section to Module Branding in his blog post. This enhancement allows module developers to associate an image with their extension product. However, to take advantage of this addition, extension developers would normally have to create two separate releases: one to use for DotNetNuke 5.x, and another for DotNetNuke 6.x (even if there were no other changes) This was the only option outside of the developer moving their development to DotNetNuke 6 or greater only. Luckily, we added a last minute addition to avoid this potential hurdle.
If you are a DotNetNuke extension developer, you are probably familiar with the .dnn manifest file. If your not familiar w/ the .dnn manifest file, it basically tells DotNetNuke how to install an extension as part of the (module, skin, menu, etc.) installation process (You can review technical details about manifests via our Wiki).
As of DotNetNuke 6, we will support both a .dnn manifest file (what is normally used) as well as a .dnn6 manifest file. In installs prior to DotNetNuke 6 (RC or public release), this .dnn6 file will simply be ignored. In DotNetNuke 6 (RC or public release), this manifest file will be read instead of the standard .dnn manifest file (thus allowing you to include both in a single installation package). Please keep in mind, outside of the new additions the same rules apply to the .dnn6 manifest as they do for the .dnn manifest file (they really are the same thing).
A couple reasons that may make it worth your time to create a .dnn6 manifest:
One last thing that I think is important to note is that if your module is only going to support DotNetNuke 6 or greater (for whatever reason), there really is no reason to create a .dnn6 specific extension manifest, simply use the .dnn manifest as you would have in the past.