Description
#26671 reduced clutter while looking at exceptions, however made working with internal-vendor stuff harder. In larger projects it's not uncommon to have private packages and use them in the project. It's very useful to actually see them in stack traces.

Ideal solution
When vendor part of PSR-4 namespace matches current project namespace code should be treated as belonging to the project..

Simple solution
Maybe we can add configurable whitelist for vendors based on vendor/[directory] which should be ignored while deciding on the code being vendor vs. non-vendor?

ping @javiereguiluz