Thank you Nir,
it somehow magically worked in spite of that, these two files have got two different files' extensions (csv and obj).
Interesting thing that before you posted your solution I tried download these files through Excel Power Query and I did. Then I tried to read it into R but it took ages and finally hung.
Thanks again.
aaa <- readr::read_csv("https://stat.ethz.ch/pipermail/r-sig-meta-analysis/attachments/20180730/e790230b/attachment-0001.obj")