Similar content is now broken up into separate .conf files in directory
/etc/modprobe.d so that individual packages can now have sole ownership
of a file rather than trying to pack all their parameters into a single,
hard to maintain file.

in what order are the files processed?

--
Among the maxims on Lord Naoshige's wall, there was this one: "Matters of great concern should be treated lightly." Master Ittei commented, "Matters of small concern should be treated seriously."
(Ghost Dog : The Way of The Samurai)