Some links are broken in the reference website, I think are those related to Tasks. For instance, in page Tasks all pages under "See Also" are broken. The address they point to, for example for MultilabelTask: https://mlr.mlr-org.com/reference/makeMultilabelTask.html should not have "make", because this one works: https://mlr.mlr-org.com/reference/MultilabelTask.html
The same happens in the functions within the example.