It is on our documentation:
When using SAML with Dashboard, the user must first authenticate with the IdP. This is referred to as IdP-initiated SAML. After the user has successfully authenticated and been directed to Dashboard, they will be granted access if they have a valid role and the IdP is correctly configured.
Note: Only IdP-initiated SAML is supported at this time.
https://documentation.meraki.com/General_Administration/Managing_Dashboard_Access/Configuring_SAML_S...
For Google's documentation, I recommend submitting feedback. This can be done by hovering over any of the text on the page, and clicking the Feedback button to the right: