I have to say that I don't really know, I just used the commands you mentioned in one of the emails and it it seems to work OK ;)
Sure, I don'texpect making 1,10 or 100 copies of the files first could interfere in any way with installing them. The question is whether it is necessary at all. When I used these cammands to install by hand, I did not make any copies, but ran the xdg commands directly on the files in the source tree. That (of course) worked, but it still works, although afterwards I moved the icon files away to the pixmaps soure directory. And I experimented renaming the pgn-viewer desktop file, and clicking a PGN file kept bringing up XBoard. There also would not have to be any fuss about name collisions of desktop files if they had to be stored in a xboard directory. So I made some changes in Makefile.am to install directly from the sources. I also changed the name of the tourney icon to application-x-chess-trn, which at the same time fixed the previous typo.
