Smart-Seq3 intron+exon meaning

Question

[Evlampia]

Hello guys, I am wondering in here https://academic.oup.com/gigascience/article/7/6/giy059/5005022?login=true , Figure 1, when they plot "intron.exon", what is meant by that? In the text they say that reads overlapping with intronic and exonic seq are then only assigned to exon only. So, what is this overlapping exon+intron in the plot (Figure1)?

Thank you! :)