Is Pro Bono work considered outside employment?

I work part-time in the day and am free after lunch. I have a design background and was a UX designer for several years and would like to continue honing my design skills.

I want to do pro bono volunteer design work for non-profits. My work states that any and all conflicts of interest must be disclosed as well as outside employment. Obviously I wouldn’t volunteer for rival / competitors.

I looked at our Outside Employment policy, and it says any employment, including temporary or part-time jobs, must be disclosed. It says volunteering is not considered secondary employment though.

Pro bono graphic / UX designer work is considered volunteer work, right? It is unpaid and from my own free time. I’d obviously use my own personal laptop and Adobe / Figma account. I’m not sure if by “volunteer work” they mean volunteering at a soup kitchen or animal shelter. They did not specify.