As you can below this image, the green thing is show Champion Status (Attack Damage (AD), Armor, Ability Power (AP), Magic Resist (MR) and more. Below Champion status is Rune Status. But below Rune Status, what is that thing? I didn't see any info show on that one.
Its called "Eternals", here is the definition from LeagueOfLegends FAQ.
What are Eternals? Eternals are a new type of cosmetic that let you showcase your accomplishments in League, counting both unique and general gameplay milestones on a per-champion basis. In-game, you’ll see milestones "pop up” on the side of the screen as you hit statistical checkpoints for that Eternal.
Other in-game features include a new flair for that champion's Mastery emote, a list of Eternals at the back of a champion's loading screen card, and a showcase of your Eternals on enemies' death screens when you take them down. You can track your progress for each Eternal in the Progression tab of the client when not in game.
https://euw.leagueoflegends.com/en/news/game-updates/features/faq-eternals-coming-patch-917
