What is [PT,L] option in RewriteRule in .htaccess file?

What is [PT,L] option in RewriteRule in .htaccess file?

Can anyone explain the meaning of [PT,L] in the "RewriteRule"
statement(2nd line of code) below
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
# Rewrite all other URLs to index.php/URL
RewriteRule ^(.*)$ index.php/$1 [PT,L] ##This is the line I am
refering.
</IfModule
This is a small snippet from my .htaccess file. Thanks.