It's developed by the main Lemmy dev as far as I understand. Closest thing to an 'official' app we've got. But other apps just suit me better ATM. I'm still testing different apps now and then since the apps are still rapidly being developed and dying out. Settled on Liftoff initially, but I remember liking Thunder and so far Raccoon is looking promising.
Yeah it seems a little spartan. But, it's probably going to be the most up-to-date whenever there is an update to Lemmy itself since it's the same dev.