[bregma]

If you're qualifying for a true senior position, and if you haven't done something outside of work in the decades of your professional experience, it's a bad sign. If by "senior position" you're thinking something that can be done by a 25-year-old with over 5 years of experience in a specific product, your resume is already on the discard pile.

I recruit a lot of work-term students (and have filled a few senior positions in the past). I always look for side projects. I always check github accounts for unmentioned side projects. Side projects tell me more about who the applicant is than a resume does. I hire people, not resumes and not previous positions of employment. Folks who are interested and enthusiastic about their field are better to work with.

Honestly, it's pretty rare that anyone lists a side project on their resume, so it's not absolutely required. When it's there, though, it usually makes the interview better ("tell me about your side project") and it's often the difference between getting an interview and not.