Regular Expression - Question regarding pattern matching

Hello together,

I got the following string:

<?xml version="1.0" encoding="UTF-8"?>
<user>
  <user ritaID="METADIR">
    <item desc="RASL Std. GPNR" name="testibus" value="562532525"/>
  </user>
</user>

I ve done the following regex (i know there are easier approaches but I prefered to train some of the more advanced methods):

Why does this regex work properly?

$string -match '(?<!value=)((?<Number>\d+)(?="/>))' 

result : 562532525

but this cuts me off the first part of the number? (value=", instead of value=)

$string -match '(?<!value=")((?<Number>\d+)(?="/>))'

I am just wondering why because it hasnt dawn on me .. :-)

thanks in advance!

Regards / Freundliche Grüsse King Julien