Hello,
to remove the the line just delete line 106 from index.php “, it is
<div class="article-footer"><hr></div>
or set class article-footer to display:none.
To remove the complete “Proudly…” remove the follwing from footer.php:
<a href="https://projectdmc.org/support/topic/remove-footer-and-fitting-page-with-retrogeek-theme/<?php echo esc_url( __("https://projectdmc.org/', 'retrogeek' ) ); ?>" class="imprint">
<?php
/* translators: %s: WordPress */
printf( esc_attr__( 'Proudly powered by %s and RetroGeek-Theme', 'retrogeek' ), 'WordPress' );
?>
</a>
Hope it helps.