These badges are about badges specific to DevCentral, and not an OpenBadge implementation.
Badges could be used to better identify users or to add adventure game flavour to the tracker.
If you create a new badge, this is the current proposal of color key:
|Poor||Gray||Small tokens, to commemorate participation|
|Uncommon||Green||Members of interest groups|
|Rare||Blue||Members of groups with takecare responsibilities|
|Epic||Purple||More valuable tokens than grays, to celebrate an achievement|