What is the technical term for this style lighting?
Indirect lighting.
example here

Usually the light source is hidden by an archtectural feature, so the feature is constructed by normal building means and then the light source is hidden in it. 

At my house we have one strip light hidden in an open topped curtain pelmet and another hidden behind an one of the exposed rafters.

These are 5' flourescent tubes with 40 year old iron ballasts.

Led strips could be hidden in a cornice moulding. etc.

it's going to be tricky to clean.