Zucchini don’t have a lot of flavour by themselves and it’s a bit unusual to find them in a salad, but this recipes which adds pasta, beans, mustard and red capsicums seems to take care of that problem.
I like the little note that Mum’s written on the top of this cutting – Like a Quiche – which suggests she either made it herself or it was made by someone else and she liked it. It does seem to have a strange combination of ingredients, especially the cabbage, but it could be worth a try.