I'd like to submit a request to have the Phish Alert Button added as an official Gmail Add-on provided by the GSuite Marketplace. We are seeing major pain points with the extension-based addon including a lack of compatibility for Mobile or non-Chrome users.
Therefore, we are forced to have users Forward phishing emails to a dedicated internal email address, but this leads to additional issues. Forwarded phishing reports are often blocked by Gmail's spam filtering which can not be disabled for outbound emails. This skews the results of our simulated phishing tests as spam filtering scans emails for links which produce a false positive in the campaign results.
Having the PAB made available as a Gsuite Marketplace Add-on should resolve all these issues. In the meantime, we will have to look into third-party solutions like Demisto's Phishing Addon.