I guess this option means your contribution or volunteer work to the community outside of your job. Such as engaging in technical forums, Github and Stackoverflow. This also includes talking in a workshop in front of large audience.
I was also stuck at this point but then I remember I had been engaged on Google webmaster forums where I dedicated roughly around ~1000 hours. I had ~100 best answers and thousands of upvotes. I also had been occasionally engaged on Stackoverflow so I will show these 2 in my application. Not sure if they are applicable or not but I am a bit optimistic so lets see
I consider each item, of what you have listed above, as a potential candidate to be a piece of evidence for How do I demonstrate that I have been recognised for my work outside of my immediate occupation that contributed to the advancement of the sector?
I believe that what matters is impact and for this particular criteria it is important that you have done it outside of your 9-to-5 occupation. I also strongly believe that it doesn’t matter whether it’s Udemy course or a lecture at Harvard University. What matters is the impact, how many people have been reached, general user feedback, monetisation (if applicable) and most importantly why have you done it?