.htaccess - difference between RewriteRule ^(.*)$ & RewriteRule (.*)$ -

when moving pages old domain new domain, noticed people added ^and other not in rewriterule

what different between

rewriterule ^(.*)$ http://mynewdomain.com/$1 [r=301,l] 

and

rewriterule (.*)$ http://mynewdomain.com/$1 [r=301,l] 

thank you.

it better use start , end anchors (^ , $) wherever possible ^(.*)$ in 2 cases listed both rules behave similar.