Move ~/.porthole configuration to ~/.config/porthole as per freedesktop.org standard. <quote> There is a single base directory relative to which user-specific configuration files should be written. This directory is defined by the environment variable $XDG_CONFIG_HOME. $XDG_CONFIG_HOME defines the base directory relative to which user specific configuration files should be stored. If $XDG_CONFIG_HOME is either not set or empty, a default equal to $HOME/.config should be used. </quote>
Please file this upstream.