2017-12-15 UTC
# 
Zegnat gRegorLove, GWG, right under the Mf2\Parser::parse() method there is Mf2\Parser::parseFromId() that parses only element with a specified ID and and their children: https://github.com/indieweb/php-mf2/blob/master/Mf2/Parser.php#L1292-L1314 😅