Honestly, as with most other tools that you have to care about but don't want to: just follow the spec https://support.google.com/webmasters/answer/6033049?hl=e

Honestly, as with most other tools that you have to care about but don't want to: just follow the spec https://support.google.com/webmasters/answer/6033049?hl=en https://support.google.com/webmasters/answer/6033049?hl=en