At present we ask people to create a librenms user (some may do this, some may run as root and some may choose their own user). However we have no idea what has been done.
I've added a config.php option $config['user'] that is now set within the users config (not in defaults.inc.php as I don't want to add this to everyone - some are not running librenms as librenms user).
We then use that in validate.php to tell people when files are no longer owned by that user and print the list. logs is excluded as this is by the web server user.
Added support for specifying user in config and then validating install
Updated validate.php docs
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