For those who are wondering, this is how ARC journal rankings work (and as you can see we at JET really wanted what is signified by that "A" ranking; "A*" would be even better but we'll have to work on it):
Tiers for the Australian Ranking of Journals
Overall criterion: Quality of the papers
Typically an A* journal would be one of the best in its field or subfield in which to publish and would typically cover the entire field/subfield. Virtually all papers they publish will be of a very high quality. These are journals where most of the work is important (it will really shape the field) and where researchers boast about getting accepted. Acceptance rates would typically be low and the editorial board would be dominated by field leaders, including many from top institutions.
The majority of papers in a Tier A journal will be of very high quality. Publishing in an A journal would enhance the author’s standing, showing they have real engagement with the global research community and that they have something to say about problems of some significance. Typical signs of an A journal are lowish acceptance rates and an editorial board which includes a reasonable fraction of well known researchers from top institutions.
Tier B covers journals with a solid, though not outstanding, reputation. Generally, in a Tier B journal, one would expect only a few papers of very high quality. They are often important outlets for the work of PhD students and early career researchers. Typical examples would be regional journals with high acceptance rates, and editorial boards that have few leading researchers from top international institutions.
Tier C includes quality, peer reviewed, journals that do not meet the criteria of the higher tiers.