Where is there any documentation on what "Active" means in the top left of the Gerrit web interface when viewing a Change?

Source:

change status in Gerrit

The change status shows the state of the change:

• Active:

  The change is under active review.

• Merge Conflict:

  The change can’t be merged due to conflicts.

• Ready to Submit:

  The change has all necessary approvals and may be submitted.

• Merged:

  The change was successfully merged into the destination branch.

• Abandoned:

  The change was abandoned.