Seems like whatever constitutes a strong password determined by their JS script when registering a new account:
jQuery(document).ready(function(){
jQuery("#password").keyup(function () {
var pw = jQuery("#password").val();
var pwlength=(pw.length);
if(pwlength>5)pwlength=5;
var numnumeric=pw.replace(/[0-9]/g,"");
var numeric=(pw.length-numnumeric.length);
if(numeric>3)numeric=3;
var symbols=pw.replace(/\W/g,"");
var numsymbols=(pw.length-symbols.length);
if(numsymbols>3)numsymbols=3;
var numupper=pw.replace(/[A-Z]/g,"");
var upper=(pw.length-numupper.length);
if(upper>3)upper=3;
var pwstrength=((pwlength*10)-20)+(numeric*10)+(numsymbols*15)+(upper*10);
if(pwstrength<0){pwstrength=0}
if(pwstrength>100){pwstrength=100}
jQuery("#pwstrengthbox").removeClass("weak moderate strong");
jQuery("#pwstrengthbox").html("Strong");
jQuery("#pwstrengthbox").addClass("strong");
if (pwstrength<75) {
jQuery("#pwstrengthbox").html("Moderate");
jQuery("#pwstrengthbox").addClass("moderate");
}
if (pwstrength<30) {
jQuery("#pwstrengthbox").html("Weak");
jQuery("#pwstrengthbox").addClass("weak");
}
});
});