... there are no GT or LT symbols in OP's sample
    my $email = 'someuser@example.com'
hence, dot star swallows all, in the relevant example.

If the relevant example is
    my $email = 'someuser@example.com'
    $email =~ /(.*) (<.*>)/;
    say "1='$1' 2='$2'";
from the OP, then dot star – i.e., (.*) – swallows nothing at all. The  '<' and  '>' characters are required to match, therefore there is no match, no swallowing, no capturing, nuttin'. As pointed out elsewhere, not even $1, $2, etc., are altered. In fact, because the first  (.*) capture group is followed by a required  ' ' (space), the angle brackets don't even figure in:  .* will initially grab everything, then backtrack repeatedly to try to match a space; finding none, it will eventually give up everything it grabbed and announce its miserable failure, triggering overall match failure.