Hi Gideon,
That is a heading three 'h3' tag with the 'sectionname' class (soon to be changed in M2.6 - MDL-40829) and is therefore controlled by the theme styles. So to change it and all the other section names in all courses alter the 'h3.sectionname' definition in your theme.
At the moment I'll see what MDL-40829 does and decide if that element in the shade is better separating from the section name type concept and changing it to a 'h2' etc. If that is what you would like in the mean time, then please tell me the version of Moodle and the Grid format and I'll tell you the line of code to change.
Cheers,
Gareth