The Html file is being used by Design Manager, and created as when you activate Publishing Infrastructure Feature. Html file doesn't come with team sites template.
Update after your comment:
It is something that you should decide at top level site of a new Site Collection, whether or not the publishing feature will be needed within that Site Collection because this can greatly impact the decision on which site template is the best choice for the top level site. If top site has publishing feature activated, so the subsites will inherit publishing, or else subsites based on team site template will eventually be converted to publishing with no real connection of publishing site collection as a parent. Also, master pages provisioning (.master/.html ) is decided at top site level, which largely decided if the site collection is publishing/team.