What do the different colored paths mean on the commit page of bitbucket?

[Emily Dirkse]

When commits are made on the commit page between different people, there are multiple lines that have different colors and intersect on the left. What do these lines and colors mean? My guess is that they are different branches merging with each other, but I am not sure if that is right. 

[Matija Varjacic]

They are indeed different branches and their merges.