How to print a taxonomy term's field value alongside a Views grouping header?

Question

In Drupal 8.4.4 I have a "Living Things" taxonomy vocabulary. One field on the terms in the vocabulary is "Most Common Name", with machine name field_most_common_name. On my "Animalia" term its value would be "Animal".

In Views, I have a "Taxon Media" view which lists media related to the taxonomy term. I display it in a block on the taxonomy term's pages themselves (not on nodes). In the view I group media by another field, "Primary Taxon", which is a reference to the term. It prints on the page as the grouping heading (e.g. "Animalia").

How can I print the value of my "Most Common Name" field next to that title? i.e. "Animalia Animal".

I have made a template, views-view-grouping--taxon-media.html.twig, cloned from the one in the Classy template, tested that works, then added the 4th line and tried a few other things such as content.field_most_common_name, but cannot get the field's value to display:

<div class="view-grouping">
  <div class="view-grouping-header">
    {{ title }}
    {{ field_most_common_name }}
  </div>
  <div class="view-grouping-content">{{ content }}</div>
</div>

Answer 1

Thanks to Mario's helpful hint in the first comment, I was able to do this in the View and not in the twig template:

1. In the FIELDS section of the View, add "Most Common Name" as a field.
2. Select "Exclude from display", because I only want it in the title, not the results themselves. (3. Select "Link to the Taxonomy term", because I want it to be a link.)
3. Next to "FIELDS", under the "Add" drop-down menu, choose "Rearrange".
4. Drag "(field_primary_taxon: Taxonomy term) Taxonomy term: Most Common Name" above "Media: Primary Taxon" > Apply
5. Click "Media: Primary Taxon [hidden]" field
6. Check "Override the output of this field with custom text"

7. REWRITE RESULTS > and copy the required tokens from the "REPLACEMENT PATTERNS" list, and paste into the "Text" area. I also inserted brackets outside of those tokens, so my Text area looks like this:

   {{ field_primary_taxon }} ( {{ field_most_common_name }} )

8. Apply > Save > Clear all caches if necessary > Refresh the page.

9. Title now in my example is "Animalia (Animal)". "Animalia" and "Animal" are links to the taxonomy page.