How to access the Vendor Extensions in swagger schema

I am customising the template and I have to fetch data from the vendor extension (e.g. x-internal-id). Inside the route i can see that its available at the route.raw in procedure-call.ejs of modular. But when trying to access it like route.raw.'x-internal-id', i am getting error in client generation.

Please help how can i access Vendor Extensions (https://swagger.io/specification/v2/#vendorExtensions).