Once the Matrix Theme is chosen the text is visible on the Themes page however not on either the Typography or Settings page
Ah it seems it’s because of the green strike through highlighting the row. (Matching the text color) We’ll have to fix!
This one (and similar for ‘Caution’ I think?) should be resolved in TestFlight #4.
Yes Phill, both the themes are fine in TestFlight #4 
Great, will mark this as solved.