No, he addresses that. Get a day job. Then do your project on nights and weekends, or else manage your manager into making it part of your job.
In most cases you'll either be told to stop or in the worst case your employer will claim they own it.
That is unless you agreed to a contract that forbids from holding multiple jobs.
40h/week paying the bills leaves plenty of free time to do something on the side when you don’t have kids / a family to take care of
Show of hands: How many others feel this way?
Personally, I can barely muster the energy to do much hacking after a normal job. The only way I've found to do work I've been known for is by blowing off my other responsibilities (sometimes to the annoyance of various people).
1: One needs downtime, and can't expect perfect utilization even after planning for rest.
Nobody really cares about you in the org and in the world in general.
There is a legal implication on side projects on everyone's contract -> so the solution here is to just have an alternative profile on social media...
Oh and don't add HR people on your linkedin.