Why is there no version 3.7 option for package "python3-devel" (but there are 3.6 and 3.8 options)?

[My Name]

In the Cygwin installer, the version options for "python3-devel" are
several sub-versions of 3.6 and a ("Test") version of 3.8, but there's no
option for any 3.7. However, "python37-devel" is another option in the
installer. Why? I have never understood exactly the difference between the
"python3-devel" package and the "python3x-devel" packages. Thanks.