Safari still accepts packaged extensions not hosted by Apple but typically requires them to be signed. I think the concern here is only partially whether this person is doing something malicious - that seems quite unlikely.
uBlock's author previously gave control of the uBlock project to someone who worked on the Safari port and this person turned out to be a (young, but I guess you can start anytime) sleazebag. uBlock's author ended up renaming his project uBlock Origin end eventually stopped contributing/backporting his work into the Safari port. The Safari port essentially died.
It's great that someone is picking this up again and wary and hopeful users are looking for some indication this seemingly awesome person is not a sleazebag.
uBlock's author previously gave control of the uBlock project to someone who worked on the Safari port and this person turned out to be a (young, but I guess you can start anytime) sleazebag. uBlock's author ended up renaming his project uBlock Origin end eventually stopped contributing/backporting his work into the Safari port. The Safari port essentially died.
It's great that someone is picking this up again and wary and hopeful users are looking for some indication this seemingly awesome person is not a sleazebag.