Gnome Mahjongg history
Gnome Mahjongg saves its high scores for each user in that user's directory often in ~/.local/share/gnome-mahjongg/history file. That is a text file composed of three columns separated by spaces. First column shows the time with UTC offset, the second shows the difficulty level and the last shows the time it took to complete the game in seconds.
There is no username, because each user would have their own high score file and would not be able to see other's scores anyhow.
2015-01-17T17:46:45+0300 easy 357 2015-04-22T14:35:45+0300 easy 370