vRO REST API: querying workflows by categoryID

In PowervRO we have a function Get-vROWorkflow which uses the vRO REST API to query workflows:

PowervRO/Get-vROWorkflow.ps1 at master · jakkulabs/PowervRO · GitHub

One of the options is to query by categoryName using the following URL:

"/vco/api/workflows/?conditions=categoryName=$($Category)"

We have a request to enhance this function to instead be able to query by categoryID. I tried the following, but it did not work and also could not find any documentation on how to discover what other 'conditions' are available:

"/vco/api/workflows/?conditions=categoryId=$($CategoryId)"

Is it possible to query the workflows API using a categoryId as a condition? If so, how should it be formed?