One of the happy surprises switching to Ubuntu again from the ever increasingly bloated Windows (10) was to find the simple KWin Rules, very clear and with focus stealing prevention (its so disruptive to have a random or background confirmation pop up while working on something in Windows).
Anyway, I have one default one for application windows, and then others for specific windows (and then a setting for krunner screwed it up and so I'm trying to export all before resetting), but I just realized export only does them one at a time. And I couldn't find any location for the actual config to backup. Below are a few links I could find and it doesn't look like there is a way export in bulk, am I wrong?
No response about a location for the config data: https://forum.kde.org/viewtopic.php?f=17&t=157045
General lack of import/export of KDE settings: https://www.reddit.com/r/kde/comments/8f4az2/is_there_a_way_to_export_and_backup_kde_setings/ and https://www.reddit.com/r/kde/comments/3bi2k1/is_there_a_way_to_export_settings_in_kde/
As suggested by @DK Bose, ~/.config/kwinrulesrc is where these settings reside.