When making websites with Joomla, I sometimes need to indicate the subcategory titles in category blogs.  The result should look like this:

 Subcat title A
 Article 1
 Article 2
 Article 3
 …
 Subcat title B
 Article 1
 Article 2
 Article 3
 …
 Subcat title C
 Article 1
 Article 2
 Article 3
 …

On the current website that’s how my publication list is formatted (Books, Edited volumes, Articles etc. are all subcategories of Publications).

Joomla can sort the articles by subcategory, but doesn’t output the subcategory title above the relevant set of articles. I made an override for blog.php for that. It's here on github.