What do the upgrades with the star icon mean in the grimoire?

[FinalZe|2o]

https://i.imgur.com/CScODc9.png

My Scarlet here is maxed at level 5, but as you can see from the image, not all of her upgrades have the star icon under them. I'm curious what it means when an upgrade has that icon under them and how to get them for the rest of her upgrades.

[FinalZe|2o]

Thank you for the response. So the star icons don't mean anything else? I swear it feels like I have a chance of getting better rarities for those particular upgrades. However, seeing as the devs seem to value horizontal instead of vertical progression when it comes to unlocks, those icons being simple progress indicators makes sense.

[Veraxx]

I understand that these stars show which skills / talents were used when beating the game, but does it unlock something later ? Why the teasing with a " x / 30 " ? It's not explained in the game and it seems that the answer to your question has disappeared.