Here I would use the fact that "attribute values" follow an = sign and do:

#!/usr/bin/perl -w
use strict; 

while( <DATA>)
  { chomp;
    my @atts= (m{=                  # an equal sign
                  \s*               # optional spaces
                     "              # a double quote
                      ([^"]*)       # capture while no double quote
                             "      # the closing double quote
                              }gx);

    print "$_: ", join( "-", @atts), "\n";
  }

__DATA__
type="car" of make="Ford" color="red"
type="car" of make="Ford" color="red" foo
foo= type="car" of make="Ford" color="red" foo
foo= type="car=" of make="Ford" color="red" foo
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