The macro makes sure that if you change domain, the warehousing URL's are updated. Useful when you're testing out the new site on a sandbox domain.
Also some tips about Transmit settings and an explanation of the difference between absolute and relative paths
6.54 transmit instelling
51.11 absolute relative
1.06.00 download
1.08.22 fluid url
https://www.youtube.com/watch?v=I-Ig_xaqRIE