The language is PAWN script, which is a C-like syntax.
You can find a scripting manual right here!
Please note: The power of Biamp Project Designer lies within our drag and drop configuration of AV systems and using scripting completely defies the whole concept of easy programming and maintenance.
From Biamp we encourage you not to use scripting code in your projects, unless you are able to develop and maintain it yourself in your organization. We are not able to help you in Biamp support regarding any issue related to the use of script code in a Project.