GitLab team member here. I participated in the CEO shadow program with Sid (aka sytse) in 2019 and it changed my career and life. Happy to answer questions about my experience.
Our values were frequently referred to during discussions and decisions were often debated in the context of our values. I had been working at GitLab for about 6 months when I joined the program and it was amazing to see our values be such points of emphasis to our leaders.
Having worked in a number of other organizations in the past, I can't recall one single "company value" from any of those orgs. In contrast, I don't think I'll ever forget GitLab's CREDIT[0] values.
During the shadow program, I realized such emphasis on our values starts at the top.