When I run
dgraph zero --help, its says
--raft string Raft options idx=1; Provides an optional Raft ID that this Alpha would use to join Raft groups. learner=false; Make this Zero a "learner" node. In learner mode, this Zero will not participate in Raft elections. This can be used to achieve a read-only replica.
Which looks like this sentence has been copy-pasted from the
dgraph alpha --help:
Provides an optional Raft ID that this Alpha would use to join Raft groups.