A look at the whole page makes it (very slightly) easier to see what’s going on here.
1742
Jan
28= 1742/43 (1743 in the modern calendar)
David Williams &
Joanna WilliamsThey are bracketed together; then, after the bracket ...
P(ar)och(ie) de Cwm jou, Com. Mon.= of the parish of Cwm Jou in the county of Monmouth
which is probably this parish -
https://www.genuki.org.uk/big/wal/MON/CwmyoyAfter the second bracket ...
Mat [...]
p(er) Licen(tiam)= in marriage [...] by a Licence
Looking at the other entries on the page, the missing bit here could be an abbreviated
coniuncti sunt = 'were joined', but that’s pretty much guesswork. I think
Lic... (for Licence) is clear enough, though it is below your red box.
As they were from outside Brecon, it would make good sense that they married by licence rather than banns.