Complete reference guide to ZQL + specific query help

Where can I find a complete reference guide to the Zephyr Query Language for Zephyr Squad Cloud?

For instance, I need to do a very simple query in our tests, finding test executions assigned to current user.

In the server version, it was just appending "assignee = CurrentUser()".

But in the Cloud version it seems to be "assignedToAccountId" = (and here it seems you can only insert a specific user id)?"

Any help for the 2 questions above