what does 'ACE' means?

[fido20160817]

Hi, what does 'ACE' means? Does anybody know? Thanks

[xmgChauncey]

You can check the code of this block in run_UI.py file and note the file path!

[fido20160817]

You can check the code of this block in run_UI.py file and note the file path!

I want to know whose abbreviation it is. Besides, according to your understanding, what's ACE?