This appears to be a contradiction in terms, because foil as a noncount noun
is normally metallic and therefore cannot be transparent. It led to confusion today in this thread:related discussion: Blumenstrauß - #25
In some of several previous discussions, Norbert did find some evidence that foil as a count noun
is occasionally used to mean a transparency for an overhead projector -- but IIRC, only in BE. So that entry probably needs to be changed to
foil [coll.] [Brit.]
- die Folie (für Overhead-Projektor)
If 'transparent foil' really is another possible term for cling film BE aka plastic wrap AE, or for cellophane, it probably also needs to be marked [Brit.], or perhaps only in industrial use, or just uncommon. And if Zellglas (which I've never heard of) really means cellophane, then that entry might also need attention.