Whenever a deployed barrel explodes (that means a dying unit exploding doesn't trigger it) without killing something other than a 'supporting structure', this message appears:
<WML> Warning: failed to match [secondary_unit] in [kill] with a single on-board unit
Whenever a deployed barrel explodes (that means a dying unit exploding doesn't trigger it) without killing something other than a 'supporting structure', this message appears: <WML> Warning: failed to match [secondary_unit] in [kill] with a single on-board unit