Do not do anything non-work related on company equipment! Ever, for any reason, seriously don't do it! Do not even research the idea! Assume the company is logging everything. They likely are. Honestly, I'd just focus on work and learn if you are just starting out. Learn as much as you can while employed by other folks (they are basically paying you to learn). Learn as much about the business your company is in too. For example, say you are a software dev at a VFX company. You might only care about your specific dev project in a tiny silo. But, learn the larger context of where your piece fits into the bigger company picture or industry. Learn about your company, where it fits into the bigger picture, where are things headed in your industry. This will open all types of jobs opportunities as you can pivot around in your industry. Why are you doing what you are doing? This will really help you down the road when you start your company as you want to think of the larger workflows and where you fit in. Focus on workflows as the underlining tech constantly changes (but workflows rarely do)! Running a company is a 24/7 thing, you will not get weekend or nights off, so don't burn yourself out working for someone else and doing your own thing useless you really think it will work. I have tons of 10% complete projects that I thought where good ideas but never panned out. So, just play around and see what might work. Don't take it all the way unless you are really sure.

If you want a job at something like gitlab. Hangout on their open-source project, learn their codebase, and send in patches. Even if they are simple docs patches. Send in 50 of those and you will start to learn the devs. Ask one of them what it is like to work there, ask them to refer you, etc. The CEO of gitlab is constantly on HN (I swear he has an alert for mention of gitlab). So, he will likely see this post. My point, take some initiative and try not to go through the conventional recruiter pipe (apply on website and no one ever gets back to you cycle). Doing this, has worked out really well for me in the past, and it will work for you too. Sure, it is more work but gets you ahead of everyone else as you are making an effort. Be strategic about this and really choose who you want to work for and go after them. Having something like, hey, I patched 50 minor typos in your code/docs goes a long way, between you and some nobody!