API key

You will need to unzip the plugin.
Then open this file in a text editor: bp-xprofile-location\inc\pp-field-type-location.php
And paste your Key where it says ‘Paste Your Key Here’. Don’t delete the single quotes. Save the file. Re-zip the plugin.

Instead, could you provide a constant to define in wp-config that would provide the key?

Otherwise, it may be better to recommend setting the key via the theme’s functions file. For example:

function custom_add_google_api_key() {
	add_option( 'pp_gapikey', '[API_KEY_HERE]' ); 
}
add_action( 'init', 'custom_add_google_api_key' );