IIRC the initial .info files (icon data needed by AmigaOS in order to
start particular install shell scripts) were created by Frank Neumann.
The others are by Christian. All were intended for distribution with the
install CDs (but Christian should perhaps confirm that). My impression
was that these files are created by some sort of resource editor which is
part of AmigaOS, so there's no source (though the file format should not
be too difficult to reverse engineer).
Uh, well... IconEditor is part of every AmigaOS installation. But there's no
magic in the file format and usually there should be tools that can convert
from/to *.info. At least http://linux.die.net/man/1/infotopam gives a short
description of the format and I wouldn't mind if someone would replace the
old icons with some (smaller) new ones. ;)