Changing ALT-tag for logo in wordpress

Use the following code to replace the original code:

if(!get_theme_mod('site_logo_dark')) echo '<img width="'.$logo_width.'" height="'.$logo_height.'" src="'.flatsome_option('site_logo').'" class="header-logo-dark" alt="your alt information here" />';

i.e. you’re replacing alt="'.$site_title.'" with alt="your alt information here".

What the '.$site_title.' means is the echo statement ends at the ' and then the PHP variable $site_title is appended to the string, and then the string reopens with the '. The . is a string concatenation character in PHP.