Microsoft’s office URI schemes conflict with the list separator of allowed_href_schemes.
https://docs.microsoft.com/en-us/office/client-developer/office-uri-schemes
I can’t allow scheme like ms-excel:ofv|u|https
for the full link ms-excel:ofv|u|https://contoso/Q4/budget.xls
Having an escape character or quoting the scheme string would be great.