At the beginning, I thaught that it would be better to remove the major version from sys.platform on all platforms. When I started to write the patch, I expected to change only 2 or 3 files. But the patch is now huge ("26 files changed, 105 insertions(+), 121 deletions(-)"), which means that it will break most third party projects.

> I would propose to do this *only* selectively,
> and *only* if experts of the platform request such a change.

Ok, I (now) agree. So let's close this issue.