This encyclopaedia contains lots of spoilers - you should play through the campaigns first before reading too much here!
Beacons
Beacons are used to draw your attention to specific locations on the map...
What are beacons?
Beacons are pulsating orbs that float above the map (usually) and minimap to draw your attention to a specific location or object.
You can right-click a beacon on the minimap to instantly scroll to that location on the 3D map. Or, if you've got units selected, you can left click on the minimap to send them to that location.
On the 3D map, you can click a flashing beacon to stop it flashing! It will still be visible, both on the 3D map and the minimap, but it won't flash any more.
Blue beacons
These are used to highlight oil resources:
Select a truck or combat engineer and then click on the oil resource to build an oil derrick on top of it. Also, make sure you have one power generator for every 4 oil derricks you build, otherwise the derricks will stop working.
Red beacons
These are the most common beacon, used to highlight where the enemy is or what the enemy just attacked:
In all game modes, they are used to highlight which of your units of buildings was just attacked. In this specific scenario, the beacon only appears on the minimap.
In scripted missions, such as Campaigns, they are used to highlight the location of enemy bases or places to investigate.
In multiplayer games they are used to highlight a map location for your allies (see "Placing beacons" below).
Green beacons
These are the rarest of the three beacon colours. They indicate the presence of technology artifacts:
Select a tank or cyborg and then click on the artifact to collect it. Once collected you'll get a message letting you know what was found, and if it's something of use it will appear in the list of available technologies to research when you click on a research laboratory.
Placing beacons
For developers
Developers can implement beacons using the following features:
addBeacon() – adds a beacon for allies or a specific player
eventBeacon() – triggers when you receive a beacon
And because In-game Chat is often associated with beacons, you'll probably need these as well:
chat() – sends a chat message to specified player(s)
eventChat() – triggers when you receive a chat message