Checkboxes can also have an indeterminate state (usually with a "-" in place of the checkmark), like the ones you can see at the below link (and which your link

Checkboxes can also have an indeterminate state (usually with a "-" in place of the checkmark), like the ones you can see at the below link (and which your link also mentions). https://storybook.react95.io/?path=/story/controls-checkbox--default https://storybook.react95.io/?path=/story/controls-checkbox-... I think the ternary checkbox has two uses: when it's a master checkbox, showing whether all of the binary checkboxes in a group are selected, and it may also be used on its own (the UI may have different actions for the three possible states).