<?php
 
$string = 'some gibberish here [tab title="Emergency Contact" important="true"] some additional info here';
 
$regex = '~
            (?:\[tab\s         # looks for [tab + whitespace literally
            |                  # or
            (?!\A)\G\s)        # (?!\A) = negative lookahead
                               # to make sure the following is not the start
                               # of the string
                               # \G matches at the end of the previous match
            (?P<key>\w+)       # match a word character greedily to group "key"
            =
            "(?P<value>[^"]+)" # " + anything not " + ", save this to group "value"
         ~x';                  # verbose modifier
preg_match_all($regex, $string, $matches, PREG_SET_ORDER);
foreach ($matches as $match)
    echo "Key: {$match['key']}, Value: {$match['value']}\n";
?>

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