[Question] Show full group titles in giveaway list?

I don't know exactly what you mean but have a look at ESGST

I think you are looking at choice 2.6.3

This is how it looks like. The groups that i am a member of are highlighted.

I am not sure exactly what you are asking, but if you look at the upper-right of the giveaway description screen, you will see a green button for the included groups in that giveaway. Clicking on that button will take you to the Groups page for that giveaway, listing all of the groups selected for it. Clicking on any one of those will take you to that group's page where you can find information connected to that group.

On EGST search for "Giveaway Groups" and "Group Highlighter"
For both to work you need to sync your Steam Groups