Done.
Sample ruleset:
alienDeployments:
- type: STR_TERROR_MISSION
forcePercentageOutsideUfo: true # percentageOutsideUfo will be forced even though this is not UFO crash/landing site
customUfo: STR_HARVESTER
mapScripts:
- type: URBAN
commands:
- type: addUFO
- type: addCraft
- type: fillArea
blocks: [3, 4, 10, 11, 12, 13, 14]
freqs: [3, 3, 2, 2, 2, 2, 2]