Description:
------------
get_browser() incorrectly handles entries from browscap.ini files when they have "+" sign in the pattern match. The "+" in the ini files is a LITERAL character, not a wildcard match. The only wildcard that browscap.ini source files use are "*" and "?".
The result of that is that none of the browscap.ini entries that have a match pattern with "+" ever match the browsers that they are supposed to match.

My suspicion is that if you'd change https://github.com/php/php-src/blob/master/ext/standard/browscap.c#L110 and add:

case '+':
  t[j++] = '\\';
  t[j] = '+';
  break;

everything would be fixed. But I haven't tested that.

Test script:
---------------
// browscap.ini entry:
// [Mozilla/5.0 (compatible; AhrefsBot/*; +http://ahrefs.com/robot/)]
// Parent="Search Engines"
// Browser="AhrefsBot"

echo "<pre>";
var_dump(get_browser('Mozilla/5.0 (compatible; AhrefsBot/4.0; +http://ahrefs.com/robot/)'));


Expected result:
----------------
object(stdClass)#2 (35) {
  (...)
  ["Browser"]=>
  string(9) "AhrefsBot"


Actual result:
--------------
object(stdClass)#1 (34) {
  (...)
  ["browser"]=>
  string(15) "Default Browser"