I've seen many different GitHub accounts and I'm always trying to browse all repositories. Very often I come across some university or bootcamp projects and I ignore them because I don't know what part of the code was really written by the candidate himself/herself. Sometimes I see recruitment tasks done for other companies and if they were solved within last few months, they usually tell me enough about the programmer. My favorite repos are those for personal projects where you can really see how much heart a person puts into programming.
Some candidates tell me their favorite/best representative repo, some do not. You're right, I should ask them - I shouldn't judge a candidate by his/her 5-year-old repos ;-)
However, during the interview, when I see different projects mentioned in a resume, I usually ask the candidate to pick his/her favorite project and discuss it. When I see projects made with different technologies (Symfony/Laravel, React/Angular), I like asking which framework he or she prefers and why :)
We're a place where coders share, stay up-to-date and grow their careers.
We strive for transparency and don't collect excess data.