Builders have icons over their head, making it easy to determine when you get a new builder and what they're doing. This synergizes well with the mark-for-leave, Stormwalker-style feature of my MoreHotkeys mod.
Changelog
-v1.0.0 - initial release
-v1.0.1 - I discovered I need to add API mod as dependency. - I changed from the old exclamation point icon to the builder's hammer icon -- the same icon from the top left species panel.