Each 'uxxx' part is the rawcode of the object editor field and then immediately afterward is the data for it. For example: ua1m Abilities\Weapons\RocketMissile\RocketMissile.mdl
TRIGSTR_ are all located in the .wts file (the map's string table) of the map's MPQ. You can either open it in that or you can also just view them specifically in game by doing something like call BJDebugMsg(GetLocalizedString("TRIGSTR_158")). (GetLocalizedString might not be necessary, I don't remember)
That is the Attack 1 - Missile model. Other fields follow the same manner. However, I believe some of the data is encrypted and therefore can't really be made out.
However, I'm not sure why you would need to decipher the .w3u, unless you are trying to view a protected map or something.