Looks to me like it was a 3 speed 'Turd' that someone made into a 'fixie'. Originally had 26" wheels, hence the 700c replacement fork. The rear brake bridge was removed to clear the 700c rear wheel, and as an afterthought some bozo made a new rear brake bridge for frame integrity. The bottom bracket lugs and seat tube lugs look ultra cheap. Lots of turds are made into fixies nowadays by mechanically challenged young people. Just my 2 kopecks....