Where can I change social icons in this Jekyll theme?

My website is here charliebunt.github.io built on the excellent “starving artist jekyll theme” and now I’m just wanting to configure the social icons and I can see in main.css there is code using ‘icomoon’ but I am confused how to update or change it. Twitter is no longer a bird icon but now an X icon and anyway I’d like to know how to work it. I cannot find where in the code you can change and add social icons within this theme.

there is an include called socials, in there it looks like it is just css where the class is icon-whateversocial.

{% for socials in site.data.socials %}
	  <li class="right"><a href="{{ socials.href }}"><span class="icon-{{ socials.title }} socials"></span></a></li>
	{% endfor %}

inside /_sass/icomoon/_base.scss it is setting what happens for each of those like:

.icon-googleplus:before {
	content: "\e600";

i assume \e600 is an icomoon icon but not sure, never used it. But I am fairly sure this is what sets the icon and if you change it it should show.