We have these tags with the same description:
The version history of Graylog is a bit confusing: It started as Graylog, then came Graylog2 (up to 0.92), then came Graylog (which is now at 2.51). So it makes no sense to have a tag graylog2 as that would (if taken literally) only apply to very old versions of Graylog.
And since there will be Graylog 3.0 this summer, it makes even less sense (or do we really want to have a tag graylog3 etc?).
I question the need to have different tags for different versions.