While working on Real Homes theme, I came across this requirement to build a breadcrumb for property custom post type that should be based on deepest term of a chosen custom taxonomy. So, I am going to share the solution I came up with. This solution can be further refactored and improved based on your needs.
While using WordPress customizer api I got confused with how default value parameter is handled by setting. As I realised that setting do not save default value in database and instead one is supposed to use default parameter for get_theme_mod. I personally found it difficult to provide default value parameter multiple times as part of get_theme_mod call. So, I wrote little extra code to save the default values in database.