[cirpis]

This seems like a needlesly defensive answer. If there are no examples then just say so. It is mathematics after all, some of it is beautiful to explore just for its own sake, no examples or applications neccesary.

But claiming a technique is a bridge between disparate areas of mathematics and then subsequently failing to give concrete examples of such bridging is a bit odd, dont you think?

For what its worth the book "7 sketches in compositionality" (https://arxiv.org/abs/1803.05316) has a chapter on topos theory which provides a good introduction with some simple examples!