The character ring and the Fresh score
For anyone reading the two small indicators under the draft.
The ring tracks length. On X it fills toward 280 (links count as 23), switches to a countdown when 20 or fewer characters are left, and turns red when you're over. On the other sites, which allow far more than a good comment needs, the ring tracks a sensible length for that site and only turns red at the site's real limit; the number is the character count.
The Fresh 96% badge shows how new the wording is next to your pasted point and your last 60 replies. Hover it to see why it dropped: Some wording repeats your pasted point. or Some wording repeats one of your recent replies. Your link's address is left out of the comparison. A draft that fails this check while it's being written is rewritten quietly before you see it Read, write, check, polish.