How do I tell what program is asking for a password?

How do I tell what program is asking for a password?

I'm getting an occasional "Authentication request" dialog from Gnome, and
I don't know what program is asking or even which account it's talking
about.

[email redacted] is an email address of mine, but I've used that address
for more than one account, and they all have different passwords. I don't
know what it's asking for. This dialog tends to pop up when I unlock the
computer after having been away for a while. I just click Cancel, and the
dialog goes away for a while. I don't get any other message when I do
that.
I'm running Gnome 3.8.3 on Arch Linux.
Note: After writing this question, I thought of checking Online Accounts
in Gnome Settings. I noticed that it showed my Google account (under that
email) as "credential expired". Is that what was causing it? I signed back
in to my Google account, but it's too soon to tell if that fixed the
problem. And I still want to know how to tell who's asking for my password
(and for which account).