Hello,
Making some testing of v2.5-dev (nighty 2013-04-29), I noticed that the "Heavy weapon" proficiency seems "to disappear", and that leads to few differences between UFOpaedia and in-game mechanics.
Examples : Riot Shotgun, Flame Thrower
UFOpaedia -> Riot shotgun and Flame Thrower requirements are "Heavy weapon"
Equip Soldiers (or Buy/Sell) -> Requirements changed to "Close combat"
In fact, looking more closely at details in the "Equip soldiers" screen, I seems that heavy weapons do not rely on "Heavy weapon" proficiency anymore... Is it still of use? Or deprecated? Or "Work in progress"?