unicorn production configuration

I see my unicorn error file growing, and I can't find out why.
It log some path but when I try them on my browser, I don't see any issue neither redirection.

I'm using rails and this is a snippet of my unicorn production conf file:

stderr_path "log/unicorn.error.log"
stdout_path "log/unicorn.log"

One line from the error log file:

xxx.xxx.xxx.xxx, yyy.yyy.yyy - - [16/Mar/2019:20:13:54 +0100] "GET /fr/yyyyyyy HTTP/1.0" 200 - 0.0926

I thought 200 means that it was OK, but why do I see HTTP/1.0 when my site is only https?
More over, why do I get all those log entries when all the reported errors are working correctly for me?
Is there a way to format log so that I can get more info on error?

Solution

HTTP/1.0 is the protocol, this does not imply that your site is not using HTTPS.
By default, the Unicorn logger will write to stderr. So these are not errors, just logs of requests coming in.

Refer this for unicorn configuration options and their meanings - https://github.com/phusion/unicorn/blob/master/examples/unicorn.conf.rb