In article <mailman.1087.1570362019.2651.bug-gnu-emacs@gnu.org> you wrote:
> "Bob" <purchasebyemail1@comcast.net> writes:
>>   struct Bar<::Foo1>         // "(show-paren-mode)" does not match `>` to `<`
The pertinent < and > are not being marked with
syntax-table text properties, hence can't be recognised as parens.