The GNOME extension appears to get the currently focused window information (ie name, title, PID and executable name) and make this information available over DBUS for the client binary.
The client binary calls gnome-screenshot -f
and I assume gives a path that the client binary then sends to Hubstaff servers.
A janky suggestion would be to create a Kwin Script that pulls the active window information, sends it (somehow) to a DBUS service that can provide it to the client binary and create a wrapper script around spectacle
to pretend to be gnome-screenshot
(eg spectacle -b -f $@
)
I don't know if this would work fully though as the client binary strings seem to hint it checks the running version of GNOME Shell, and without an account I can't see if this is a hard requirement or a "Hey, this is broken, we'll try our best!" type thing.