regex101: PCRE (Legacy) Match Workspace

Regular Expression

<my:group1>(.*)<\/my:group1>

New

<?xml version="1.0" encoding="UTF-8"?>
<?mso-infoPathSolution solutionVersion="1.0.0.182" productVersion="15.0.0" PIVersion="1.0.0.0" href="http://sp01/hp/Therapy/Forms/template.xsn" name="urn:schemas-microsoft-com:office:infopath:Therapy:-myXSD-2013-03-01T10-07-30" ?>
<?mso-application progid="InfoPath.Document" versionProgid="InfoPath.Document.3"?>
<my:myFields
        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xmlns:pc="http://schemas.microsoft.com/office/infopath/2007/PartnerControls"
        xmlns:ma="http://schemas.microsoft.com/office/2009/metadata/properties/metaAttributes"
        xmlns:d="http://schemas.microsoft.com/office/infopath/2009/WSSList/dataFields"
        xmlns:q="http://schemas.microsoft.com/office/infopath/2009/WSSList/queryFields"
        xmlns:dfs="http://schemas.microsoft.com/office/infopath/2003/dataFormSolution"
        xmlns:dms="http://schemas.microsoft.com/office/2009/documentManagement/types"
        xmlns:xhtml="http://www.w3.org/1999/

Substitution

<?xml version="1.0" encoding="UTF-8"?>
<?mso-infoPathSolution solutionVersion="1.0.0.182" productVersion="15.0.0" PIVersion="1.0.0.0" href="http://sp01/hp/Therapy/Forms/template.xsn" name="urn:schemas-microsoft-com:office:infopath:Therapy:-myXSD-2013-03-01T10-07-30" ?>
<?mso-application progid="InfoPath.Document" versionProgid="InfoPath.Document.3"?>
<my:myFields
        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xmlns:pc="http://schemas.microsoft.com/office/infopath/2007/PartnerControls"
        xmlns:ma="http://schemas.microsoft.com/office/2009/metadata/properties/metaAttributes"
        xmlns:d="http://schemas.microsoft.com/office/infopath/2009/WSSList/dataFields"
        xmlns:q="http://schemas.microsoft.com/office/infopath/2009/WSSList/queryFields"
        xmlns:dfs="http://schemas.microsoft.com/office/infopath/2003/dataFormSolution"
        xmlns:dms="http://schemas.microsoft.com/office/2009/documentManagement/types"
        xmlns:xhtml="http://www.w3.org/1999/