Open elements/assets/admin/metabox.js
and find line 185:
text: value.name
Replace it with:
text: elements.showID && value.id ? value.name + ': ' + value.id : value.name
Then, open elements/class-metabox.php
and find line 97. On the line below it, add this:
'showID' => apply_filters( 'generate_elements_show_object_ids', false ),
It should look like this:
'choose' => __( 'Choose...', 'gp-premium' ),
'showID' => apply_filters( 'generate_elements_show_object_ids', false ),
Now you can add this function to your site:
add_filter( 'generate_elements_show_object_ids', '__return_true' );