I see nothing of substance here to comment on, and only have two minor editorial comments.

In Section 2:
   The lists of algorithms are ordered such that, if multiple
   algorithms are permitted by the client, the algorithm that appears
   first in its list that is also permitted by the server is used for
   the SSH transport layer connection.

I found this a little awkward to read, and it also seems that the ordering is only significant for the client list, and not for the server list.  May I suggest this minor re-wording?:

NEW
   The lists of permitted algorithms are in decreasing order of usage
   preference.  The algorithm that appears first in the client list
   that also appears in the server list is the one that is used for
   the SSH transport layer connection.
END

In “Since the module in this document only define groupings”, make it “modules”, plural, to match “define” (three instances).