All that, in theory, would be tracked. The senior engineer would be able to point to the PRs/MRs with all the helpful comments that led to the code improvements

All that, in theory, would be tracked. The senior engineer would be able to point to the PRs/MRs with all the helpful comments that led to the code improvements. It wouldn't be hard to show calendar invites or whatever for pair programming sessions, which could be corroborated by asking the junior as well. It does, however, bring up the point that one should always be mindful of what their output looks like and how easy it is to prove. I'm sure everyone has worked with a 'meeting commando', who loves to discuss edge cases and bikeshed instead of shipping code. Maybe they've carved out a nice niche doing so, and have convinced others in the company of their (dubious) value, but it shouldn't be surprising when the company is sold/acquired/RIFd that someone else might expect someone with an engineering title to have more tangible contributions to point to.