bp_attachments_get_template_part( string $slug )

function bp_attachments_get_template_part( $slug ) {
	$switched = false;

	/*
	 * Use bp-legacy attachment template part for older bp-default themes or if in
	 * admin area.
	 */
	if ( ! bp_use_theme_compat_with_current_theme() || ( is_admin() && ( ! defined( 'DOING_AJAX' ) || ! DOING_AJAX ) ) ) {
		$current = bp_get_theme_compat_id();
		if ( 'legacy' !== $current ) {
			$switched = true;
			bp_setup_theme_compat( 'legacy' );
		}
	}

	// Load the template part.
	bp_get_template_part( 'assets/_attachments/' . $slug );

	if ( $switched ) {
		bp_setup_theme_compat( $current );
	}
}