Unfortunately, the theme does not have such option so it would not be possible without manually customizing the theme code in order to add custom text into the template I am afraid.
However, in case you would like to look into the code, the portfolio list related files are:
Dear Paul,
How can I display some text at the top of each portfolio category which would appear like the portfolio item ?
Hi Emilie,
Unfortunately, the theme does not have such option so it would not be possible without manually customizing the theme code in order to add custom text into the template I am afraid.
However, in case you would like to look into the code, the portfolio list related files are:
1. template-all-works.php
2. /template-parts/portfolio-listing.php
3. /template-parts/portfolio-listing-loop.php
4. /uxb-templates/single-portfolio.php
5. /uxb-templates/taxonomy-portfolio.php
Regards,
Paul