Listeo Core has separated folder for all the templates that are used to display single listings and listings archives. Those templates files can be overridden via your theme if you want to customise them. To override a template, move it to
yourtheme/listeo-core/, keeping the path within ‘templates’ intact.
So for example, you’d like to change the part that displays Gallery on single listing view. To do that, copy file
wp-content/themes/yourtheme/listeo-core/single-partials/single-listing-gallery.php and you can customise the file as you need. It will be used instead of the core template file. This also supports child themes, so you can put that file directly to your child theme.
Please note, if these files are updated in the core plugin, you may need to update your custom version in the future to maintain compatibility. Therefore it is advised to only override the template files you need to customise.