Drop CONFIGURING file as it's unmaintained for at least a decade
Summary:
It still mentions dcop, so nobody updated it since the introduction of
dbus which is > 10 years. If nobody updates it and nobody complains that
it mentions dcop it means nobody reads it.
Reviewers: KWin
Subscribers: kwin
Tags: KWin
Differential Revision: https://phabricator.kde.org/D17712