See https://sourceforge.net/p/sevenzip/discussion/45797/thread/65ad3ef7/#9227
sourceforge provides sha1 and md5 hashes over https
Sourceforge redirects to plain http if you are not logged in. (that's of course very stupid behavior of Sourceforge, but who we are to ask them to fix it)
So it's useless for those who does not have account here.
(I hope I do not have to explain to you why hashes should not be delivered through plain http. Or do I?)
By the way, it's possible and easy to implement https totally for free, for example by using https://letsencrypt.org/ (that's the preferred way actually), so if you were just scared of https because "it requires paying money", that's simply not true. And even earlier there were CAs who offered domain-validated certificates free of charge.
Why do you want to download over HTTPS? I see no reasonable benefit...