What are the coloured dots next to the board size buttons on the new matching screen?

[shinuito]

See

Automatch updates 2024-12-10

Hello All, Based on a lot of feedback and increased levels of pondering the Play page has been updated again. Most notably: You may now select multiple board sizes and multiple time settings to search against by activating the “Multiple” option from the drop down Two new indicators have been added, a green dot which indicates there is someone within your rank range that is ready to play now, and a gray dot which indicates a popular setting in the past 30 minutes by players within your select…