Open Source Assertion IP

Is there a website that provides open source assertion IP? I’m looking for a collection of UART assertions.

In reply to StunkMan:

Is there a website that provides open source assertion IP? I’m looking for a collection of UART assertions.

I am not sure if protocol specific assertions are available but Accelera’s assertion library has collection of many base properties (called OVL). You have to break down UART properties and map them to the properties available in OVL.