OMG. It will seem strange. But I for some reason considered that .svn folder occupies about 1 Gb. I cruelly was mistaken
Sorry, my bad. I failed to see the subdirectory sizes under .svn. The actual size here is about half a GB. Maybe it grows when you modify and update often.
I don't use it much for development, I use Git instead.
Interestingly, the .git directory of Lazarus Git repo got by git-svn link is smaller. It is a little over 100 MB although it contains all the commit history since 2015. In a mirror with full history it is over 300 MB, still way smaller than the .svn dir.
Wow!
It means Git can be recommended when HD size is of concern.