Hm... For tooltips, try looking at "Human/Orc/NightElf/UndeadUnitStrings.txt".
EDIT: Weapons, abilities, and general other data is found in their respective SLK files.
war3.mpq\units\UnitWeapons.slk
war3.mpq\units\UnitAbilities.slk
war3.mpq\units\UnitData.slk
First open Excel, then export the file. And then open the file from excel. If you try to open it directly from the MPQ after exporting, it'll probably crash.