No Chrome browser as main requirements source

We have long epoch and experience supporting IE in web applications, trying to implement Microsoft “standards” and now we are back is similar situation.

• Requirement: should support Chrome, is too abstract. What exactly? NTLM also? Really?
• Mozilla: We implement standards only (for now we know there are some exceptions in that promise - PWA installation support for example). But still FF == WEB standard (or almost).
• Chrome Standards = standards - something + N x f(). That means, not all things are implemented (as long they are not promising something similar to Mozilla, currently not) added N number of unknown functionalities.

When Chrome is requirement:

1. What exactly should be implemented or what functionalities should be considered and supported?
2. Who makes the list (analysis) of unknown functionalities?
3. Who makes the list (analysis) of missing standards functionalities?