Aspects are currently unreleased and a part of the magic system! Some more info on magic & the aspects can be found at:
the end of
this lore page
this QNA answer about the constellations
this QNA answer about the missing magic
this QNA answer about what seasons each aspect is tied to
towards the end of
the development plan (post beta section).
The gist of aspects currently is that not cats start off with their magic being undiscovered, and then once the magic update comes out there will be a new adventuring location where we can get a magic rock after beating the boss for the first time that will give a chance of a not cat discovering their magical aspect. (This is the 6th daily activity, the one that is always greyed out!) What aspect a not-cat gets is based on the season they were born + luck, as some aspects are rarer than others.
(edit: found another magic link and added it!)