Letters in the upper-right corner

[unmerged(51702)]

What are the letters in the upper-right corner next to the patch number?

Mine says: HoI2 1.2 (AQHQ) what does this mean?

 

[jpd]

Those letters denote the checksum, as calculated over the essential game data files. It's used to validate, in multi player, that all players work with the same set of data in those data files.