Session files in tmp/sessions with size 0

[anonymous-matomo-user]

I just noticed that there are thousands of files in tmp/sessions and the vast majority has a size of 0. Age of all files is at most around 16 days.

Should these files really exist?

[robocoder]

Session files are managed by the php runtime, and fall into web server configuration territory. Check your php.ini settings. There are settings to clean up session files.

http://php.net/manual/en/session.configuration.php