Halo Infinite has been rated in Australia.
The newly minted classification for the game confirms a mature rating (M) for Australian audiences based on themes and language with "mild impact" and violence with "moderate impact."
It's worth noting that the Australian classification board has slightly stricter ratings than those of other countries, most notably the ESRB in the United States and PEGI in Europe. An M rating marks content "not recommended for children under the age of 15," meaning an M in Australia is basically the same as a T in the states or a rating of PEGI 16 in European countries.
For comparison, just look at the last mainline Halo game, Halo 5: Guardians, which was rated T for Teen in the US due to blood, mild language, and violence. The game's PEGI 16 rating references similar material. Halo 5 was likewise rated M in Australia for themes of mild impact, language and nudity of very mild impact, and violence of moderate impact. So if anything, according to Australia – and who am I to argue with Australia – Halo Infinite may be slightly less explicit than Halo 5.
In any case, this rating affirms that Halo Infinite won't noticeably deviate from the series' usual tone. Apart from that, it doesn't tell us much. The Australian rating mentions "violence, online interactivity, and in-game purchases" but we already knew those were a thing. But if nothing else, it is exciting to see a new Halo game pop up on ratings boards, if only as a reminder that it's coming soon – possibly in November, if a number of rumours prove correct.
Speaking of in-game purchases: new reports suggest Halo Infinite will have wackier skins than previous games.