We have started working on this. ETA is Q3 this CY.
An error occurred while saving the commentJames Sturtevant commented
This looks like the it might be available: https://docs.microsoft.com/en-us/azure/application-gateway/rewrite-http-headers#rewrite-conditions
"You use the Perl Compatible Regular Expressions (PCRE) library to set up regular expression pattern matching in the conditions. "