[Sebb767]

A lot of people had local domains (only entered in their hosts file or the router) on the dev TLD. Adding that domain to the hsts preload list not only broke their current setup, but also made it hard to bring it back to live - if you don't own the domain, the only option is to set up your own CA, with all included drawbacks.

[spcebar]

I thought a host file entry overrides dns resolution— wouldn't a .dev domain that's already pointed at localhost not be affected by this? Or am I misunderstanding?

[addingnumbers]

No matter what your DNS says, browsers are hard-coded to refuse to send requests via plain HTTP on a TLD with HSTS required (like .dev).