BA-scale Heat Sensors seem to have a clear niche: while less powerful than other sensor packages, they're very lightweight and still capable of detecting enemy units, even through intervening buildings and stealth armor.
They show up on two canon suit designs, and the fluff in TechManual indicates they're found on as-yet-unpublished industrial exoskeletons as well.
And yet, for reasons I can't fathom, the listed Availability Rating for Heat Sensors is X-F-F-F. Why is this supposedly so vanishingly rare?
