based on https://langille.org/tmp/FreshPorts-email-parsing.tar.gz

1 - untar

[dan@empty:~] $ tar -tzf /tmp/FreshPorts-email-parsing.tar.gz
tmp/FreshPorts/
tmp/FreshPorts/2019.09.05.13.50.02.69461.txt.raw
tmp/FreshPorts/mail.txt
tmp/FreshPorts/process_mail.pl
usr/local/lib/perl5/site_perl/FreshPorts/
usr/local/lib/perl5/site_perl/FreshPorts/process_svn_mail.pm
usr/local/lib/perl5/site_perl/FreshPorts/config.pm
usr/local/lib/perl5/site_perl/FreshPorts/constants.pm
usr/local/lib/perl5/site_perl/FreshPorts/branches.pm
usr/local/lib/perl5/site_perl/FreshPorts/email.pm
usr/local/lib/perl5/site_perl/FreshPorts/process_mail.pm
usr/local/lib/perl5/site_perl/FreshPorts/utilities.pm
usr/local/lib/perl5/site_perl/FreshPorts/process_cvs_mail.pm
[dan@empty:~] $ 

2 - run

[dan@empty:~] $ cd /tmp/FreshPorts
[dan@empty:/tmp/FreshPorts] $ perl process_mail.pl 2019.09.05.13.50.02.69461.txt.raw 
Message-Id: 201909051349.x85DnwLa079972@repo.freebsd.org
List-Id: SVN commit messages for the ports tree for head
Subject: svn commit: r511189 - in head: devel/py-convertdate devel/py-fbprophet devel/py-holidays devel/py-lunardate math/py-pystan
<?xml version="1.0" encoding="ISO-8859-1"?>
<!DOCTYPE UPDATES PUBLIC "-//FreshPorts//DTD FreshPorts 2.0//EN" "https://www.freshports.org/docs/fp-updates.dtd">

<UPDATES Version="1.3.2.1">
    <UPDATE>
        <DATE Year="2019" Month="9" Day="5"></DATE>
        <TIME Minute="49" Second="58" Hour="13" Timezone="UTC"></TIME>
        <OS Repo="ports" Branch="head" Id="FreeBSD"></OS>
        <LOG>Add ${WRKSRC} to LICENSE_FILE

Noticed by:	koobs</LOG>
        <PEOPLE>
            <UPDATER Handle="dvl"></UPDATER>
        </PEOPLE>
        <MESSAGE Subject="svn commit: r511189 - in head: devel/py-convertdate devel/py-fbprophet devel/py-holidays devel/py-lunardate math/py-pystan" EncodingLosses="false" Id="201909051349.x85DnwLa079972@repo.freebsd.org">
            <DATE Month="9" Day="5" Year="2019"></DATE>
            <TIME Timezone="UTC" Hour="13" Minute="49" Second="58"></TIME>
            <REPOSITORY>ports</REPOSITORY>
            <REVISION>511189</REVISION>
            <TO Email="ports-committers@freebsd.org"></TO>
            <TO Email="svn-ports-all@freebsd.org,"></TO>
        </MESSAGE>
        <FILES>
            <FILE Path="head/devel/py-convertdate/Makefile" Action="Modify" Revision="511189"></FILE>
            <FILE Revision="511189" Path="head/devel/py-fbprophet/Makefile" Action="Modify"></FILE>
            <FILE Revision="511189" Action="Modify" Path="head/devel/py-holidays/Makefile"></FILE>
            <FILE Path="head/devel/py-lunardate/Makefile" Action="Modify" Revision="511189"></FILE>
            <FILE Action="Modify" Path="head/math/py-pystan/Makefile" Revision="511189"></FILE>
        </FILES>
    </UPDATE>
</UPDATES>
[dan@empty:/tmp/FreshPorts] $