Noto Serif font does not load on HTTPS sites

One of the Google fonts, Noto, does not load on HTTPS site due to a hard-coded http-only link:

<link rel='stylesheet' id='gold-essentials-google-fonts-css'  href='https://fonts.googleapis.com/css?family=Noto+Serif%3A400%2C700%7COpen+Sans%3A400%2C600%2C700&display=swap&ver=5.2.4' type='text/css' media='all' />

A protocol-relative URL should be used instead (i.e., just “//” instead of “https://”). Otherwise, modern browser will refuse to load this due to mixed-content (secure/unsecure) policies.